Terminal Server Storag

[kspare]

I'm working on a new build for our terminal servers.

E5-1630 v3 3.70GHz 10MB Cache
256GB Ram
1 400GB Intel 750 NVMe SLOG
1 1200GB Intel 750 NVME L2 Arc
24 2TB Drives. 11 Mirrored Vdevs and 2 spares

Any new server is coming with a 12gb expander, but i've had no issues running a 6gb controller.

So my question to the masses is.

How are people doing with 12gb controllers?

If you are running 12gb controller and back plane, is anyone seeing any performance advantages with 12gb drives?

Im ordering everything new so changes can be made before I order.

 

[MtK]

I don't know what you plan to use the server for, but not mirroring the SLOG is probably a bad idea.
As for the L2ARC, assuming it is really needed, 1200Gb is probably a lot...

 

[kspare]

I'll try to find the post, but the theory on them is that they would likely fail at the same time and have a huge MTBF..not really worth it.

with 256b of ram the large l2arc will work well.

We also replicate every 30 mins to another box to mitigate failure. kinda got those bases covered, looking more for performance.

 

[jgreco]

Could consider dual 750's for the L2ARC. Underprovision them to a reasonable size (800GB?) until you can check to verify that you aren't hurting yourself.

 

[kspare]

I thought someone was tryin to figure out how to under provision them but were not successful?

Anyway, im not worried about the intel 750s. I was more concerned with the 12gb controller and 12gb drives.

 

[Mirfster]

is anyone seeing any performance advantages with 12gb drives

Ship me a duplicate setup and I will be happy to test it out for you. For best results, I would need at least 12 months to ensure a "complete evaluation"... ;)

 

[Mlovelace]

I thought someone was tryin to figure out how to under provision them but were not successful?

Anyway, im not worried about the intel 750s. I was more concerned with the 12gb controller and 12gb drives.

@depasseg has been running 12Gb sas in production mabey he can weigh in.

You don't need to mirror the slog anymore, save your money don't buy two. Unless you are going to run Sync=always for your iSCSI/NFS you won't need a slog. To under provision the cache devices (l2arc) you have to add them to the pool manually through the cli.

Edit:
Here is how you add them underprovisioned (assuming two cache devices daX and daY and pool name of tank).

Code:

gpart create -s GPT daX
gpart create -s GPT daY
gpart add -t freebsd-zfs -a 4k -s 800G daX
gpart add -t freebsd-zfs -a 4k -s 800G daY
zpool add tank cache daX1 daY1

 

[depasseg]

I've been fine running 12g SAS. There have been a couple others that are running it as well. There have only been a couple cases of issues. Iirc, there is a thread that tried to capture the issues (it might have been posted by Ericloewe).

As for performance I don't think you'll notice a difference with 24 spinning drives. But you can do the quick math to see.

 

[jgreco]

I thought someone was tryin to figure out how to under provision them but were not successful?

Anyway, im not worried about the intel 750s. I was more concerned with the 12gb controller and 12gb drives.

Just make the partition size smaller, leaving those extra blocks untouched/unallocated.

Opinions on the 12G seems varied over the last few months.