Raid 5 vs 10 performance

[rcfant89]

Hopefully a quick question, I have been reading about the difference and what I have seen seems to conflict a bit. Some say raid 5 is better for reads but very slow on writes whereas 10 is the other way around. Some say 10 is better for both.

I have 5 disks I want to put in an array and my most important concern is performance. I care more about read performance than write as I mainly use it for media streaming.

I have 50 TB that I want to put in this array. I know you can only use 2x disks for raid 10, I am ok with using 4 disks and getting 20 usable TB. My question is:

Would a 5 disk raid 5 have better read performance than a 4 disk raid 10?

And I'm assuming the raid 10 would have the better write performance?

Thanks.

Edit: This is for a dell poweredge server so I do have a dedicated H700 raid card. Specs are 2x CPU 24 total cores, 32 GB ram, SSD boot drive. This array is for main datastore.

 

[Doctor Rob]

I would go with RAID 10 as if 1 disk in raid 5 goes down the whole array slows to a painful crawl.. also in most cases Raid 10 is just about always faster. IF you want faster Read then RAID 10.. Write is also most of time faster with Raid 10 as well.. but some cases it can very. Its one reason a lot of web servers have moved to RAID 10 as you have the speed AND redundancy and it does not crash the site to have 1 drive die (speed I mean).

https://www.cyberciti.biz/tips/raid5-vs-raid-10-safety-performance.html

 

[rcfant89]

Ok so you are saying it's basically faster to read and write with raid 10? That's what I have read some times but then other guides like this:

https://www.microsemi.com/product-directory/raid-controllers/4047-raid-levels

say that raid 10 is "not as fast as raid 5 in most streaming environments". I have spare disks and backups so the dead drive issue isn't an issue to me. Basically just care about performance but do like at least 1 drive (like with 5 and 10) just so I don't have to redo the whole thing if something does happen to die which is why I don't go raid 0.

 

[rcfant89]

According to this: https://www.cyberciti.biz/tips/raid5-vs-raid-10-safety-performance.html

it looks like raid 10 is better in every way, except size. Not sure why the other guide said raid 5 was faster in streaming but I guess I will go with 10. Thanks.

 

[thedrewnorth]

Also depends on what RAID Card you use, which I didn’t realize, until recently, was that HUGE of a difference.

I tried a few low-to mid range cards at first, with 8 4TB ironwolf pro’s. The performance in RAID 10 was substandard. Maxed out around 500 mb/s. I tried using the card alone, softraid alone, and a combination of hardware and software raid. Cap on the performance was 500mb/s as stated previously, with 14.5tb total storage.

I took the advice of several members here, and purchased an LSI Card. I couldn’t believe the difference.

The same 8 drive array on the LSI with battery, running RAID 5, got me 24tb running over 1000mb/s. So the performance and storage capacity difference is huge.

I just added 3 additional drives and rebuilt the array with 11 drives. 10 drive RAID 6 with hot spare. And the performance and storage is the exact same, but with 2 disk parity + hot spare.

It’s total worth it.

I’m also demoing primocache, and added a 1tb NvME as cache. Performance increase is a little hard to gauge from benchmarks, but the difference in real world is noticeable. It’s adding quite a bit of performance value.

I can lose two drives as opposed to 4 which I can deal with, pretty safe to me. All my irreplaceable data is backed up to another RAID array, and also backed up to 2 separate cloud providers.

Excellent safety there, and killer performance for long-term storage, to compliment my super fast onboard arrays.

 

[rcfant89]

Are you saying the performance was 500 Mb/s (megabits per second) or 500 MB/s (megabytes per second); there's an 8x difference between those two.

I went with a raid 10 on these disks and I can get anywhere from 150 MB/s to 300-400 MB/s so basically 1.2 - 3 Gb/s. Sad thing is I can get the same or better speeds out of my single SSD on my desktop without the multi/extremely expensive HDDs and raid card but I digress.

 

[FireWire2]

@thedrewnorth
"Also depends on what RAID Card you use" <== that is a crucial point.
My RAID with Acreca RAID card 12x drives I can get over 2500MB/s read/write speed - Anyone states RAID5/RAID6 is slow because they do not know how to do it right