Raid Z2 & 16 disks

[fuznutz04]

Hi everyone,

I am new to the forums, and FreeNas in general. I have installed FreeNas on my new Storinator box. The box is capable of holding 30 drives, but right now, I am beginning with 17 drives. 16 drives (4 TB each) for storage and 1 as a hot spare. My goal was to setup a RAID 60 type array. My thought was to setup 2 RaidZ2 arrays, striped. I also have a log drive on an SSD and 2 caching drives, also on SSDs. The main purpose of this box will be a VEEAM backup repository. Did I set up this array correctly? Does anyone have another configuration that might be better for my situation? I'm a FreeNas noobie, so thanks in advance!

 

[BigDave]

I think a bit more info may make our recommendations easier.

• How much RAM are you running?
• which model of hard disks (i.e. WD 4TB EFRX Nasware 3.0)?
• How are the drives attached (i.e. HBA card with backplane)

 

[fuznutz04]

BigDave,

I have 16 GB RAM.
HDs are HGST DeskStar 4GB (http://www.newegg.com/Product/Product.aspx?Item=N82E16822145912)
The drives are attached with an LSISAS9201 card (2 of them)

 

[mjws00]

Looks about right to me. Striped mirrors would give more IOPS at the cost of space. But for a backup repository that is kind of unnecessary. 8 drive Z2 is pretty much spot on for width leaning towards space. Adding the next vdev will still give you room for a couple spares.

Not sure the cache drives will be useful, plus you need to watch the ratio or L2ARC to RAM (Keep it under 5:1). RAM may be inadequate depending on how active the server is i.e cold storage vs frequent retrieval. Slog may prove useful assuming nfs and sync=always.

If it was mine I'd dump the l2arc ssd's in favor of RAM. End of the day it will be about network utilization.

 

[BigDave]

Just some BASIC considerations here...

• 34GB RAM would be borderline IMHO, 16GB is just not going to be enough for that size pool.
• 64GB would be much better and may allow you to drop the cache/log drives

Without knowing your exact needs it would be hard for me to say more. Perhaps someone with more
experience will follow up 4 you.

 

[cyberjock]

L2ARCs are useless for backup repositories. I'd definitely not do less than 32 GB of RAM.

 

[fuznutz04]

Thanks for you replies everyone. In reading through the manual and the forums, it's clear that FreeNAS LOVES RAM; I'll bump up to 32 or 64 and ditch the logging/caching drives. Is there a reason that the compression is only listed at 1.0x? When I was setting up the pool, creating and deleting the pool to see how the various configurations would work, at one point, I had a compression of 3.x, another time it was in the 5.x range. Why do I only see 1.0x now?

 

[HoneyBadger]

Thanks for you replies everyone. In reading through the manual and the forums, it's clear that FreeNAS LOVES RAM; I'll bump up to 32 or 64 and ditch the logging/caching drives. Is there a reason that the compression is only listed at 1.0x? When I was setting up the pool, creating and deleting the pool to see how the various configurations would work, at one point, I had a compression of 3.x, another time it was in the 5.x range. Why do I only see 1.0x now?

LZ4 has an "early abort" if it can't achieve a reasonable level of compression (12.5% space savings, IIRC) - VEEAM has inline compression and deduplication, so if you're feeding FreeNAS a data stream that's already compressed or encrypted, LZ4 will just be aborting out of everything.

 

[fuznutz04]

LZ4 has an "early abort" if it can't achieve a reasonable level of compression (12.5% space savings, IIRC) - VEEAM has inline compression and deduplication, so if you're feeding FreeNAS a data stream that's already compressed or encrypted, LZ4 will just be aborting out of everything.

I haven't used this yet as a VEEAM repository. I just set it up and have moved pictures, audio files, videos, text documents etc. to it.

 

[danb35]

Images, audio, and video are pretty much not compressible, so that would explain the 1.0 compression ratio. It would take millions of text documents to significantly change that.

 

[fuznutz04]

Images, audio, and video are pretty much not compressible, so that would explain the 1.0 compression ratio. It would take millions of text documents to significantly change that.

Yes, after I pressed the reply button I realized that. :) I will leave the compression turned on even though I will be compressing with VEEAM. I will also be backing up hundreds of SQL data bases to this box, so hopefully I see a lot better compression with those.

 

[SweetAndLow]

LZ4 has an "early abort" if it can't achieve a reasonable level of compression (12.5% space savings, IIRC) - VEEAM has inline compression and deduplication, so if you're feeding FreeNAS a data stream that's already compressed or encrypted, LZ4 will just be aborting out of everything.

Agree'ed, it all depends on the content you are writing to the pool.