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RAID01 or RAID10
For RAID enclosures with 4 or more (even number of) drives, RAID10 is one of the recommended RAID schemes, for speed and safety. RAID5 and RAID6 being the more popular RAID levels, particularly for 6 and more drive RAIDs.
Of course, RAID10 provides less space than RAID5 or RAID6.
For applications (like on set data wrangling) we have reached that point in data sizes where offloading to single drives is too slow to be considered. So, we often use 2-drive RAID 0 disks like the G-RAID or LaCie 2big or the newer Sony Professional RAIDs. And, for safety, we backup to two or even three such RAID0 disks. So, in effect, this is a ‘kind of’ RAID01
The reason for using RAID0 disks of 2 drives is size and weight. And, with 2 or 3 of them as separate units, they can stored and shipped in manageable packages. And each one of them has the data.
So, my question is, when using 4 drives in one enclosure, why is RAID10 recommended and not RAID01? Or does it make no difference?
Also, when making a RAID10 in a 4-bay enclosure, does one need to make the pairs with alternate drives? Meaning, drive 1 and 3 is one striped RAID1 disk, and drive 2 and 4 is the other striped RAID1 disk, and then one takes these two disks and striped them as RAID0.
Or, can one take drive 1 and 2 is one striped RAID1 disk, and drive 3 and 4 is the other striped RAID1 disk, and then one takes these two disks and striped them as RAID0. Does it make a difference?
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Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India -
7 Replies
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I would not do a RAID01 or RAID10. Period.
Mirroring in 2018 ?Bob
Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com -
Raid 6 gives you enough safety instead of mirroring
cheers
rainer
factstory
Rainer Wirth
phone_0049-177-2156086
Mac pro 8core
Adobe,FCP,Avid
several raid systems -
4 bay enclosures are a bit of a pain.
Mirroring always gives you 50% usable space, which is usually not acceptable. Also depending on how your RAID is provisioned it can actually be slower for sequential access.
Over 4 drives I’d begrudgingly choose RAID5, but suggest that you don’t use HDDs that are too large.
For 6x drives and above choose RAID6, or some kind of double parity equivalent.
Beyond that I’d say 16x is getting wide enough for RAID6. At that point you may want to look at R60 (thats what we do on 24x enclosures).
Also some people like to allow for a hot spare, but I’ve seen this get out of shape when storage controllers/software are left unattended. Once something fails an experienced engineer will be better at weighing up the next step.
NB: ZFS rewrites some of these rules, but I doubt that is within the scope of this discussion.
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I know the benefits of RAID 5 and RAID 6, but there is a specific use case for which I had put the question.
When shooting in remote places where magliners can’t be rolled to, and where we have a very frugal setup, we need to provide for fast but reasonably portable hard disks. For Alexa SXT/Pana Raw/Red Raw, using RAID0 is the only way to to realise drives that have capacity and speed. So we use G-Tech or LaCie. And we transfer to two of them as safety. Two RAID0 drives used in parallel (but not mirrored) were what I likened to ‘kinda, sorta’ RAID01.
Anyway, I got the answers. If life throws you a 4-bay, make a RAID5.
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Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India -
fwiw- there’s a lot of articles on the web explaining why you should avoid Raid 5 at all cost. It’s also been talked about extensively in the Adobe Hardware forum and the consensus is to never use Raid 5.
Here’s just one explanation:
https://www.askdbmgt.com/why-raid5-should-be-avoided-at-all-costs.html
Windows 10 Pro | i7-5820k CPU | 64 gigs RAM | NvidiaGeForceGTX970 | Blackmagic Decklink 4k Mini Monitor |
Adobe CC 2018 |Renders/cache: Samsung SSD 950 Pro x2 in Raid 0 | Media: Samsung SSD 960 PRO PCIe NVMe M.2 2280 | Media: OWC Thunderbay 4 x 2 Raid 0 mirrored with FreeFileSync -
Hi folks,
we’ve worked with raid5 very successfully for years without any data loss. We have used over 10 diferent raid systems (Apple Xraid, Lacie, Sonnet, etc.). When the Raids developed more and more towards Raid6, we switched to Raid6 obviously. Now, we use Raids with a minimum of 16bay Raids. Raid6 plus spare is standard, but If I had a 4bay Raid I would use raid5.
cheers
Rainer
factstory
Rainer Wirth
phone_0049-177-2156086
Mac pro 8core
Adobe,FCP,Avid
several raid systems -
Short version: RAID10 is a bunch of RAID1 pairs with a RAID0 laid down across the top of it. RAID01 is 2 RAID0 stripes that are then setup in a mirror.
In the event of a disk failure, in RAID10 the matching disk copies its data to the new drive. If a different drive fails during this rebuild, you’re fine, just as long as you have 1 disk from each RAID1 pair.
In a RAID01 situation, you’ve got 2 RAID0 volumes, so if a disk fails, once you replace it, it has to copy the entire data set from the other RAID0 volume. If a second disk fails, you may be in a world of hurt, as you are now hopeful the underlying software can assemble things from 2 broken RAID0 volumes.
In a single enclosure, it doesn’t matter if you do slot 1/2, 3/4 or 1/3, 2/4. It actually made a difference back in the day when you had external disk shelfs via external SCSI. You would mirror shelf 1 disk 1 with shelf 2 disk 1, shelf 1 disk 2 with shelf 2 disk 2, and so on – that way if a shelf had an issue (power, cooling, termination, etc) it wouldn’t take down the whole system. Lots and lots of 9.1gb SCSI & FC disks in those days, that’s how we rolled!
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