I have 2 SSDs attached to a PICE x1 controller in my servers. I had plans for them, but they are now spare.
I have 7x 8TB SATA drives in 1 pool and 4x14TB drives in another pool.
The files are video of several GB in size, once asked for a file, the server will deliver the whole thing. There may be up to 4 or 5 file transfers in place, but the total size is likley to be 200-300 GB as an absolute maximum, more like 30-40 GB on average.
The SSDs are doing nothing, would it give me a performance increase adding one drive to each pool as a L2ARC/cach drive?
I have 1 pool of 7x8tb Sata disks and 1 pool of 4x14TB sata disks. I was thinking of using one SSD as Cache for each pool.
Haveing said that I could use a PCIE to M.2 card, only 1 admittedly, and use that as a cache for the 7x8tb pool. I know the limitation of th ePCIE slot would only give me 900-ish MB/s, but still faster than a SSD, just not getting all I could out of an M.2, but there are not any other slots left.
If I did that, what size M.2 should I get? I guess enough to hold the files currently being transferred. Which worst cast would be 7 files at 50 GB each, more reasonably 4 files at 8 gb each, but even a small M.2 at 512GB should be enough.
You should post your detailed hardware listing and how you are using the server. L2ARC is better for repeated reads that arenāt in the ARC. It doesnāt sound like your reading the same files over and over again with multiple clients.
Hi SmallBarky,
Yes thatās correct. The video files are written once, and never re written or updated, They are then read by several clients, although not necessarily at the same time, but itās possible.
The Hardware is a Dell T340 with 32GB of ram, 4x14TB Toshiba N300 Sata drives forming one pool, using the onboard controller, and 7x8TB Toshiba n300 drives forming another pool, using the controller card that came with the server and was wired directly to the drive bays. There are 2 x 500GB Sandisdk SSDs attached to an additional controller using a PCIE 1x slot.
Do you need anymore information to help me?
Thanks
The controller card for the 7x 8TB pool. Is it flashed to āIT Modeā or is it a plain HBA adapter? What is the model of the controller? Are you using Mirrors or Raid-Z(1,2,3) for the pools?
BASICS
iX Systems pool layout whitepaper
Special VDEV (sVDEV) Planning, Sizing, and Considerations
The 7x8TB controller was flashed to be "compatible " with TrueNas, and sees every disk as a disk and doesnāt present 1 āraid-edā disk. The 4x14TB array is raidz0, a stripe array. The 7x8tb is raidz1, raid 5. I have a good backup so Iām on with the raid0 strie, plus I have only 1 slot for an extra drive, so Iām saving it.
The serve is down at the moent, and comes up in the evening, as the UKās electricity is so expensive. it costs Ā£0.89 or $1.12 a day to run it. I put a power meter on it!
JBOD disks on a RAID hardware controller in RAID mode are NOT the same as disks on the same controller flashed to IT mode. IT must be IT mode - please run the commands and post the output.
RAID0 on a hardware RAID controller might be OK with ZFS or might not. Since this & ZFS striping are both non-redundant, and so if you lose one disk you lose everything either way too, there is no practical difference in normal running. HOWEVER, if you see one of the 14TB drives starting to fail, your choices to copy that drive before it fails may be VERY different.
Please run the complete set of commands in my standard set and post the results.
root@truenas[~]# storcli show all
CLI Version = 007.1207.0000.0000 Sep 25, 2019
Operating system = FreeBSD 13.1-RELEASE-p9
Status Code = 0
Status = Success
Description = None
Number of Controllers = 0
Host Name = truenas.local
Operating System = FreeBSD 13.1-RELEASE-p9
StoreLib IT Version = 07.1300.0200.0000
root@truenas[~]# sas3flash -list
Avago Technologies SAS3 Flash Utility
Version 16.00.00.00 (2017.05.02)
Copyright 2008-2017 Avago Technologies. All rights reserved.
Adapter Selected is a Avago SAS: SAS3008(C0)
Controller Number : 0
Controller : SAS3008(C0)
PCI Address : 00:02:00:00
SAS Address : 5588a5a-0-f835-5900
NVDATA Version (Default) : 0e.01.00.39
NVDATA Version (Persistent) : 0e.01.00.39
Firmware Product ID : 0x2221 (IT)
Firmware Version : 16.00.11.00
NVDATA Vendor : LSI
NVDATA Product ID : Dell HBA330 Adp
BIOS Version : 08.37.02.00
UEFI BSD Version : 18.00.03.00
FCODE Version : N/A
Board Name : Dell HBA330 Adp
Board Assembly : N/A
Board Tracer Number : N/A
Finished Processing Commands Successfully.
Exiting SAS3Flash.
root@truenas[~]#
root@truenas[~]# sas2flash -list
LSI Corporation SAS2 Flash Utility
Version 16.00.00.00 (2013.03.01)
Copyright (c) 2008-2013 LSI Corporation. All rights reserved
No LSI SAS adapters found! Limited Command Set Available!
ERROR: Command Not allowed without an adapter!
ERROR: Couldn't Create Command -list
Exiting Program.
Unless the same video is downloaded again and again by multiple clients, a L2ARC cache would not be useful. Even then, network transfer is the bottleneck
