# Storage options - RAID?



## MusoD (Nov 7, 2017)

Hi Folks, 

I'm at the stage of needing another external hard drive to store photographs... which got me thinking about back up, and bigger storage solutions.

What are the thoughts on RAID systems, and how easy are these to configure and work with? It's totally new to me. 

Any recommendations on what products are good and work well? I'm Mac based, so something that works nicely with Macs would be good.

Thanks for your thoughts!


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## pwp (Nov 7, 2017)

I think what you're referring to is a NAS (Network Attached Storage). 
Go straight to the Gold Standard, Synology. Do a search and read reviews.
https://www.synology.com/en-global Go to the Value Series. 
I use an earlier version (DS1511) of the DiskStation DS1517, six years old and 100% stable.

-pw


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## MusoD (Nov 7, 2017)

Thanks PW, that's great. 

Forgive my ignorance, but do I just plug these into the computer and they essentially behave like a regular external HD?


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## LDS (Nov 7, 2017)

MusoD said:


> What are the thoughts on RAID systems, and how easy are these to configure and work with? It's totally new to me.



RAID are a first level of protection to avoid a catastrophic data loss, downtime, and the need to restore from a backup (if you have it). It can also be used to increase the size of a single volume, beyond the size of a single disk, and usually read speed (write speed depends on the configuration - they can be slower in some), because operations can happen in parallel.

They increase availability being able to survive one or two disks failures, depending on the level (but RAID0 or JBOD configurations that just increase the volume size, with no redundancy), at the expense of part of the disk space used to store redundant information. This allows to keep on working, and rebuild the array, although another failure will mean all data will be lost - a good backup procedure is still needed. The large disks of today unluckily increased the chance of another failure under the stress of rebuilding a large array, especially if disks are near the end of their life.

With most systems, and especially consumer NAS, configuring RAID is very simple. Just select the level you want, and the array will be built automatically. Once an array is created, it will appear and will be used like a single disk. You'll just need to monitor is health - and replace failed disks ASAP.

It is important to select the right type of disks. For spinning ones, there are desktop/laptop-oriented ones which are designed for speed, less fore reliability, and there are storage-oriented ones which are designed for reliability first. Some prefer to avoid disks from the same production batch, because it may increase the risk of failures at the same time.

You can use a RAID storage for primary storage, secondary or backups, but RAID itself is not a backup.

I have a primary storage which is a RAID-1 (mirror) array, a secondary one which is akin to RAID-5 (but built on ZFS, which implements a different kind of RAID), mostly because it allows to create larger volumes with a degree of safety, and then backups on other media. This configuration ensures I can keep on working if any disk fails, and a full copy of data anyway exists on other media if I need to rebuild an array.


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## LDS (Nov 7, 2017)

MusoD said:


> Forgive my ignorance, but do I just plug these into the computer and they essentially behave like a regular external HD?



A NAS is attached to the network, hence the name (Network Attached Storage) and you see it as a network share (although a volume can be mounted directly via iSCSI if supported, for example, but it is more complicated). There are also DAS systems (Direct Attached Storage) that are attached directly to a PC using Thunderbolt, USB or eSATA and will behave like regular external HD - plus the utility fo configure them.


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## Zeidora (Nov 7, 2017)

I use RAID 1 (or RAID10) like an external hard-drive, so without the network aspect. I had some NAS, but the network controller has failed on some of them, so I am rather weary of them. Unless you need the network aspect, I would go with simpler external HD configuration.
Re which RAID flavor, for additional safety, I would only consider full mirroring solutions, so RAID1 with two discs (both disks have the very same information) or RAID 10 with multiple discs (with 4 disks, 2 pairs are joined to make one larger volume, the two pairs have the very same information). I would stay away from RAID5/6, because the once one volume fails, the strain put on the remaining drives increases during re-storing, and failure probability increases for a second drive. Then the data becomes unrecoverable. See wikipedia entries for details. IMHO, the additional storage space you get with RAID5/6 is not worth the risk, given how cheap HDs are. 
I use LaCie RAID drives and am happy with them. Have 2 disc desktop, 2 disk portable, and 4 disk desktop versions.
Buffalo Tech NAS have had the network card failure. Been a while, so maybe they have gotten better.


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## MusoD (Nov 7, 2017)

Thank you all for the comments so far, I appreciate your help. 

As you say Zeidora, I'm not too worried about about the network or remote access side of things, really I guess the main things I want from it are increased storage for increasingly large photo libraries and a mirrored backup. So it sounds like some kind of RAID 01 or RAID 10 Direct Attached Storage is a good option for me.

So looking at the Synology range as PWP recommended, are there any thoughts on:

Synology DS216 two bay enclosure 
Synology DS418 four bay enclosure

Even with just these two devices, there seems to be quite a few model variations, and that's before I add the drives!

Thanks again.


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## cayenne (Nov 7, 2017)

Go ahead and pony up for the 4 bay enclosure.

I have one and it is GREAT!!


I plan to get either another couple of them, or maybe a larger unit.....

Depending on the RAID set up you use...you can increase your READ or WRITE times which helps if say you need lots of throughput for video editing, etc...

But I would vote with the others, I love my Synology NAS units.

cayenne


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## MusoD (Nov 7, 2017)

cayenne said:


> Go ahead and pony up for the 4 bay enclosure.
> 
> I have one and it is GREAT!!



 Definitely thinking this is the way to go. 

So if I get a 4 bay enclosure, could I for example add something like two 4TB drives now, and use that (mirroring one f the drives) and then add the other two later? And would it mater if the later drives were a higher capacity (assuming that I need more storage down the line and I'm guessing that larger drives are gradually getting cheaper), or do all the drives need to be the same? Sorry if that is a daft question.


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## Mikehit (Nov 7, 2017)

MusoD said:


> cayenne said:
> 
> 
> > Go ahead and pony up for the 4 bay enclosure.
> ...



Discs do not have to be the same size. 
Also be careful with mirroring - in its simplest form, a copy is created in 'real time' and that means all edits and deletions so if you delete something it is deleted from the 'mirror'. Mirroring in this way is useful if you are concerned about your disc crashing in mid-operation but it is NOT a back-up in he traditional sense because deleted data is lost. IMO discs are so reliable now that I would not even consider a mirror.
But you do need a definite back-up strategy: multi-bay NAS are great for creating back-ups after you have finished for the day and you have the choice of incremental back-up (saving only the changes) and full back-ups (saving the whole drive anew). 
Backup strategy is about risk containment and everyone has different ideas about what is sufficient.


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## privatebydesign (Nov 7, 2017)

I recently went through this same process, buy yet more HDD's and daisy chain or consolidate and upgrade to ba more streamlined and efficient storage solution.

After answering the DAS/NAS question to yourself, and that is not straightforwards, then you can start to look at feature sets.

DAS or NAS? You need to answer these questions:
1/ Do you have one workstation that you do all your image editing on? If yes then get DAS.
2/ Do you need remote access to your files outside your home network? If yes then get NAS.

DAS is cheaper then NAS, it is simple to set up and generally they are much faster to access files than NAS systems. They can be configured for speed, storage redundancy and a mix of the two. I ran an expanding DAS system for years and liked it because it could grow very easily as my file sizes grew!

NAS is more flexible than DAS and the configuration options are bewildering. But none of it could be called intuitive even when you use the simplified 'comes in the box' utilities. The truth is if you don't need remote access NAS is not the best way to go, file access is slower, it takes a lot more looking after and configuration, it is considerably more vulnerable to hacking and corruption and I probably didn't do the smartest thing in getting it.

I got the QNAP 453A with 4x 4TB set up in a RAID 5 which gives me redundancy and 12TB of space. It is a great piece of equipment and QNAP offer more bang per buck than Synology. I have mine set up as a media server as well that streams to my network attached TV and sound system and it also streams to mobile devices too so I am getting some more value out of it, Plex and on the fly transcoding are great features if you have a use for them, if you don't save some money and get a nice DAS! I am surprised at how slow image files move to and from the NAS on my main workstation, to the point that I need to do a lot more work on network switches and configurations to get a faster throughput, big composite PS files are pretty slow to open.


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## Jopa (Nov 8, 2017)

Unfortunately all proprietary solutions more or less suck. If something happens to the controller, firmware, data integrity - you're completely on your own. It's usually very hard to recover a proprietary file system. The "factory-built" NAS devices are usually small and lack proper cooling, which is also critical for mechanical hard drives. Ideally - build it yourself. The drives are cheap (large size but slow RPM), Linux is free. You need a good RAID controller with a battery backup - performance and recoverability will depend on it, and a decent size enclosure with a bunch of fans. Any motherboard, CPU and 16GB of RAM will work. For extra reliability you can add a UPS that could shut down your storage machine in case of a power outage. You can buy all parts on NewEgg, tax free.


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## scottkinfw (Nov 8, 2017)

MusoD said:


> Hi Folks,
> 
> I'm at the stage of needing another external hard drive to store photographs... which got me thinking about back up, and bigger storage solutions.
> 
> ...



You may want to have a look at Drobo 5D3.
I have several Drobos and I have been using them for about 4 or 5 years now. I really like them a lot, and I'm a Mac guy.

Here are some highlights:

* easy set up and use.
* 5 Storage bays
* mix and/or match HDD's (best however to have same speed)
* Hot swapable
* Notifies you if a HDD is about to fail
*Multiple configurations- I think it is RAID 8 (check web site)
*Runs off of Thunderbolt/ USB C* I do LR editing using the files that are stored on it.
*Use any HDD you want
*Run low on storage, add another HDD or a bigger drive.
*It is easy, it works.
*Relatively inexpensive vs. other brands
Hope this helps.

sek


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## yeahright (Nov 8, 2017)

I am also currently considering buying a NAS, since my desktop PC's hard drives are near full with photos now. Since we are two people accessing the same files from different computers in our home network, I suppose a NAS (instead of a DAS) is the way to go. At the moment I think it'll be the Synology DS918+ 4-bay NAS with two 8 TB Seagate Ironwolf HDDs configured as RAID-1 in the first two bays. What puzzles me at the moment is what backup strategy and -media will be sensible.

Buy another two 8 TB HDDs in external cases, and regularly backup onto these two drives alternately from the NAS and store both off site (so that there is always one backup off site at all times even during backup onto the other backup drive)? 
Are the NAS bay cases mechanically suited for transport so that I can simply put the backup drives in bays 3 or 4 and take them out after backup to store elsewhere (instead of external HDD cases), or are they merely delicate frames that still leave all the HDD contacts exposed and vulnerable so that it's unwise to cram them in a bag for transport?
What backup strategy: incremental or always simply mirror the NAS onto the backup drive? Will 8 TB for the backup drives for incremental backup be sufficient, or should they be larger to accomodate the larger size of incremental backups (since they also store previous file versions)? 
Are backups in a proprietary format using proprietary software dangerous anyway and it's better to have all your backups in a standard file system so that they can be read by the operating system without the use of backup software?


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## Zeidora (Nov 8, 2017)

Yeahright: Re multiple computers and access to DAS/NAS, you could give second computer remote access privileges to first computer with all its attached peripherals such as DAS; would require that first computer is running. 
Remember, networks (even 1 GB) are still slower than thunderbolt (I think it is 20 GB). There are 10 GB RJ45 copper switches (as opposed to optical), but making everything 10 GB on your network may be quite costly. So first computer would get fast access, second slower. Glass half full at least.
You could also connect the computers via thunderbolt and set up a thunderbolt bridge rather than LAN, if hard-wire is an option.
On PC, no idea.


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## LDS (Nov 8, 2017)

yeahright said:


> Are the NAS bay cases mechanically suited for transport so that I can simply put the backup drives in bays 3 or 4 and take them out after backup to store elsewhere (instead of external HDD cases), or are they merely delicate frames that still leave all the HDD contacts exposed and vulnerable so that it's unwise to cram them in a bag for transport?



Usually, no. Some NAS even don't have disk frame at all, you simply insert disks inside the slots. There are disks carrying cases or protective boxes for storage, if you need it.



yeahright said:


> What backup strategy: incremental or always simply mirror the NAS onto the backup drive? Will 8 TB for the backup drives for incremental backup be sufficient, or should they be larger to accomodate the larger size of incremental backups (since they also store previous file versions)?



It has to suit your needs - including backup and recovery times. Incremental backups are quicker, but may slow down a full recovery - but also require less space to keep more copies of a file modified several times, and perform a point-in-time recovery. There's not a size that fits all - depends on your storage space availability, how back in time you need to go, the frequency of file changes, etc.



yeahright said:


> Are backups in a proprietary format using proprietary software dangerous anyway and it's better to have all your backups in a standard file system so that they can be read by the operating system without the use of backup software?



Dangerous, if you use a reputable application, no. You'll be able to access the backup through the vendor software only, though. 

Good backup applications are designed to track what they backup and often to add enough data to check for errors, and remediate them if possible. They can also automate many tasks (scheduling, snapshots, compression, deduplication, recovery, verification, etc.). 

Some simple tools just make file copies, they just automated it, more advanced ones may use their own backup formats and databases to speed up file searches for retrieval.

Making copies to a standard file system is OK, especially if you have the experience to set everything up so backups don't require many manual steps to be repeated every time, which can lead to mistakes. Again, that depends on your needs and how complex your backup needs are. Backing up a few directories can be done with simple copies using utilities like robocopy.


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## cayenne (Nov 8, 2017)

PrivateByDesign: Just curious, what is your network speed internally?
I find I have little to no lag I can notice on my NAS units......

Just curious.....

Everyone have a great day!!

C


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## CSD (Nov 8, 2017)

Jopa said:


> Unfortunately all proprietary solutions more or less suck. If something happens to the controller, firmware, data integrity - you're completely on your own. It's usually very hard to recover a proprietary file system. The "factory-built" NAS devices are usually small and lack proper cooling, which is also critical for mechanical hard drives. Ideally - build it yourself. The drives are cheap (large size but slow RPM), Linux is free. You need a good RAID controller with a battery backup - performance and recoverability will depend on it, and a decent size enclosure with a bunch of fans. Any motherboard, CPU and 16GB of RAM will work. For extra reliability you can add a UPS that could shut down your storage machine in case of a power outage. You can buy all parts on NewEgg, tax free.



You can mount Synology RAID into a Linux distro to recover data quite easily, fans are fairly easy to swap out and to source replacements. Also Synology and QNAP offer ease of use and regular, tested updates to the core OS. If you're a geek then go for roll your own, but for everyone else then a COTS NAS is the best solution.


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## CSD (Nov 8, 2017)

Some factors to consider when buying a NAS:

1) How are you going to back it up? 
2) Does your network support jumbo packets/VLANs?
3) What other purposes do you envisage the NAS to do (VPN, OS Back up/version control, CCTV station etc).
4) How much data do you generate per annum and envisage for the future?

I currently have a 4 bay NAS to 4 bay NAS both with 8Tb drives that mirror each other on separate sites. The main data/backbone network is on it's own VLAN to facilitate throughput and jumbo packets. This is segregated from day-to-day traffic which wouldn't benefit from the jumbo packets. The NAS is also connected using a dual link 1Gb/e connection (link aggregation). You'll need a managed switch to be able to create a VLAN and facilitate LAG connections.

I also have a LTO tape drive for back ups, these are for archival and off-site storage. I know this is overkill for a lot of people, but I prefer to use something I can grow into.

*Note: * RAID isn't a back up solution, it's purely for up-time. RAID data can easily become corrupted or suffer from bit rot. That's why you need a secondary solution to back up the NAS whether it's a NAS-to-NAS or NAS-to-Offline solution such as a external drive or tape.


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## privatebydesign (Nov 8, 2017)

cayenne said:


> PrivateByDesign: Just curious, what is your network speed internally?
> I find I have little to no lag I can notice on my NAS units......
> 
> Just curious.....
> ...



Everything but my modem is 1Gb (though I haven't done actual read write tests I never seem to have the time!), my router is the DNS assigner for the network including my office switch, cables are 5e or 6. I know I do not have it running optimally and would love to find a QNAP orientated site that doesn't go off into tech speak in the first sentence or that doesn't just push you into their Apps.


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## helpful (Nov 9, 2017)

For years I've been struggling to find and not finding a good solution. I think I may have finally found it earlier this year:

https://www.datoptic.com/

I now use their Thunderbolt 2 8-bay RAID towers with my Mac Pro.

Notes:

* I use only enterprise HGST He10 hard drives (10 TB now, and formerly 8 TB).
* I use a tiered storage approach.
* Most photos, anything older than six months, are stored on enterprise RAID 1 arrays and backed up on individual enterprise hard drives.
* Due to the speed of workflow, all photos newer than six months are stored on a four-drive RAID 0 array, and backed up onto separate enterprise hard drives. Those backup drives are never accessed or spun up except when backing up photos. The RAID 0 array is ejected and powered off unless work is happening with it. Previously I never would have considered RAID 0, until an expert pointed out that the wear and tear on hard drives is actually the smallest when RAID 0 is used, and the probably of a four-disk RAID 0 failure in five years with these drives is less than 5% even when the drives are in use 24/7. If failure does happen (which I simulated to make sure), then with the backup drives data can instantly be copied to my working SSD drive or or a new RAID 1 array, if/when the RAID 0 ever experiences failure.
* Over the years, like many others, my only failure experience has been with RAID 5 and 6 (the RAID 6 eventually recovered all data, but it was very scary). I would never recommend using RAID 5. It burns out drives four times faster than normal, and probability of failure during a rebuild is scary to say the least.
* No photos are ever deleted from the memory card unless at least two copies exist on separate enterprise hard drives.
* At the end of the year a third copy of all photos is made and put into remote storage.
* Perhaps most importantly, all the best photos have already been published / sent out to clients, so even if I lost all the photos, much of my best work would still carry on strong.

I hope this helps!


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## SecureGSM (Nov 9, 2017)

Helpful,

I am sorry, your advise in regards to Raid 0 and RAID 5 is far from being helpful 

raid 0 improves write/read speed only (performance array) but increase probability of failure and data loss by 2 times - dramatically. should one out of 2 drives fail, you won't be able to rebuild the data set from the second one as each drive contains only a half of the entire data set. 
Raid 5 is a redundancy array of drives. each bit of information being written to 2 drives at a time and then next bit is written to next pair of drives, and so on and so forth. you can add additional or replace existing drives in the array as you go. there is no risk of data loss as long as at least 2 healthy drives left in the system.
you statement about raid 5 wearing out drives 4 times faster is false. RAID 5 system is an old tech and your statement is not supported by industrial evidence. I am not suggesting that your RAID system is non functional , but your explanation is far from being ... helpful 


]


helpful said:


> For years I've been struggling to find and not finding a good solution. I think I may have finally found it earlier this year:
> 
> https://www.datoptic.com/
> 
> ...


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## helpful (Nov 9, 2017)

SecureGSM said:


> Raid 5 is a redundancy array of drives [...] there is no risk of data loss as long as at least 2 healthy drives left in the system.



This is untrue.

In fact, RAID 5 uses one parity bit, so if more than one drive fails, you're toast. And when that one drive does fail, experienced sysadmins know that RAID 5 rebuilds are extremely dangerous. An amazingly high number of times another drive fails during the intense and slow rebuild process.

Here is what happens when you do just one write onto a RAID 5 array:

1. Read the old data
2. Read the old parity
3. Write the new data
4. Write the new parity

You are also incorrect about RAID 0. You stated: "raid 0 improves write/read speed only (performance array) but increase probability of failure and data loss by 2 times"

In fact, RAID 0 doesn't have ANY redundancy all all. It increases the probability of complete failure FAR more than just two times compared to other redundant levels of RAID.

However, the amortized incidence of failure per drive goes down with RAID 0 since it does not burnout the hard drives as quickly due to less reads and less writes. Also, with some extremely reliable enterprise hard drives, the chance that a small RAID 0 array will go bad is less than the probability that your RAM will go bad or your power supply will go bad, etc.

Finally, remember that RAID is NOT backup. No amount of RAID is sufficient. Just one messed up RAID controller, and even the best RAID array of all can be destroyed. Secure instant delete can even be activated inadvertently by hackers determined to do harm.

Most importantly, data must be backed up to separate disks or another RAID off of the main RAID. Period.


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## Mt Spokane Photography (Nov 9, 2017)

There are several good NAS choices, it depends on what you are looking for. I'd get a 4 -6 disk unit, it will handle not only your files, but your backups.

I prefer one that is networked, so it can be accessed by any computers or equipment on your network. One with a thunderbolt port is limited to what can use it, and has to be close to your computer.

Synology and Qnap are top choices, so look closely at them.

I'd get this one 

https://www.amazon.com/QNAP-Professional-Grade-Attached-Supports-TS-453A-4G-US/dp/B017YB7T6U/ref=sr_1_1?ie=UTF8&qid=1510203114&sr=8-1&keywords=ts-453a

It has a celeron processor, not a atom, 4 network jacks, two HDMI jacks, USB3, its capable of playing 4K video which some cannot do.

Here is a good site to read reviews and see actual test results. 

Certainly, Synology is very good, The DS916 is fast, but has no HDMI out. That only matters to some users who want to connect it to a TV set or video monitor. Pay attention to the Drobo review, its not so capable when compared to the competition.

https://www.amazon.com/Synology-DS916-8GB-DiskStation-Diskless/dp/B01EMSGNCY/ref=sr_1_1?ie=UTF8&qid=1510203673&sr=8-1&keywords=synology%2Bds916&th=1

http://www.storagereview.com/reviews/consumer/soho_nas


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## LDS (Nov 9, 2017)

helpful said:


> In fact, RAID 5 uses one parity bit, so if more than one drive fails, you're toast. And when that one drive does fail, experienced sysadmins know that RAID 5 rebuilds are extremely dangerous. An amazingly high number of times another drive fails during the intense and slow rebuild process.



There are a very large number of small RAID5 arrays in use, and if it was so dangerous it would have been abandoned years ago, although, with larger and cheaper disks RAID6 or RAID10 became more common (and nested RAID like 50 or 60 as well, but you need far more disks).

The stories you heard often come from far larger systems, with tens or hundred of disks and heavy workloads, where the sheer scale needs different approaches, because multiple disk failures became a far bigger risk. A home or studio NAS with a few disks is a different league.

Anyway, anytime you need a full rebuild or restore, you put the source of data at higher strain and you increase its risk of failure, whatever they are the remaining disk of an array, an external disk, another NAS, your backup tapes, etc. etc.



helpful said:


> Here is what happens when you do just one write onto a RAID 5 array:
> 1. Read the old data
> 2. Read the old parity
> 3. Write the new data
> 4. Write the new parity



Actually, not always - that happens for small I/O operations, when data inside a stripe needs to be changed, and not the whole stripe. That's why the stripe size (and the number of disks it is divided on) you select when creating a RAID array is not irrelevant. A "full stripe" write doesn't need to read old data - the old parity is irrelevant.

It is important if your applications write data in small chunks. RAID5 was often used for databases, that usually handle file data in small chunks of a few KB each, on several disks, and do a lot of "random" writes continuously.

When you write sequentially your 25MB RAW, or 100MB TIFF, on a few disks RAID (maybe just 3 or 4), a lot of full stripe writes will occur, and the penalty will be far smaller - only for the part of data that doesn't fit a full stripe.

In turn, the more disks needs to be read to obtain a full file content, the more I/O operations on the disks will be required. In this regard, RAID0 or RAID5/6 arrays work in the same way.

That's why the workload type matters - write intensive ones need a different setup than read intensive ones. Most photographers' NAS will be used writing files on imports or backups once, and then mostly reading them. 

That's why multiple configurations are in use - one may want to use a RAID1 or RAID10 for data that are changed frequently, especially in small chunks, and RAID5 or RAID6 for data that are mostly read, and changed infrequently.

I would use RAID0 only for data already existing elsewhere that have to be accessed at high speed (it was often used for video editing), but today, any decent SSD will outperform a RAID0, and will be more reliable.



helpful said:


> Also, with some extremely reliable enterprise hard drives, the chance that a small RAID 0 array will go bad is less than the probability that your RAM will go bad or your power supply will go bad, etc.



No. Spinning disk reliability is still far lower than RAM (especially ECC), CPU, and so on. And even a bad RAM module won't kill instantly all your data like RAID0 can. And enterprises hard drives are still used with some kind of redundancy anyway, because the costs of downtime and data loss can be too high.

Frankly, thinking a small RAID5 is more dangerous than RAID0 looks to me like being more afraid of a zombie invasion, instead of a flood or earthquake...

PS: sorry for the highly IT contents, but IMHO was need to put things in the right perspective.


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## Mt Spokane Photography (Nov 9, 2017)

I've used Raid 5 for many years and have had disks go down with no issues. Early Raid 5 systems were less reliable, and large industrial Raid systems that incorporate 12 or so drives may be more at risk merely because of the thousands of drives they use. Raid 6 is the answer if you have a large array of disks. I have a 6 drive array, and after 8 or 10 years of continuous use, one drive failed this spring, it was rebuilt successfully, but the drives were getting old, so I replaced them all. I also have a newer 4 drive array which runs 24/7. 

In any event, a Raid system is not a backup. It gives high availability, but do a proper backup always.


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