more samsung ssd woes

zedicus

Renowned Member
Mar 5, 2014
26
4
68
CPU BOGOMIPS: 67194.56
REGEX/SECOND: 1968961
HD SIZE: 881.38 GB (rpool/ROOT/pve-1)
FSYNCS/SECOND: 1203.74
DNS EXT: 20.35 ms
DNS INT: 21.52 ms (subliminal.local)


pair of 860 evos in raidz mirror 1gb drives
this is the rpool and i was hoping to share it with VM's but not with those speeds

atop shows 2% on the disks
ashift is 12
scheduler is noop

server has 64gb ram
ZFS is limited to 8gb

can this be made tolerable or do i need to toss more $ at it?
 
Hi,

this is for a Samsung EVO not bad.
What do you think you get and why can't you use it for the VM too?

But anyway for a real test you should use FIO.

Code:
fio --filename=/rpool/data/fiotest.fio --bs=[4k|128k} --rw=[read|write] --name=test --direct=[0|1] --sync=[1|0] --size=10G --numjobs=1
 
i will try that today.

i have a small old raid 5 array in my old server that gets 3300 fsyncs. i figured a pair of ssd even zfs would be way faster. guess i should have done my math instead of just assuming.
 
This comparison is not valid because your raid must use a cache what is normally an SDRAM.
SDRAM is at the moment faster than VNAND.
Also, the Samsung 860 EVO is a consumer SSD and not an enterprise-class SSD with high sync capability.
If you what increase you sync performance you can add a ZIL device like the Intel optane memory.
 
if i added an nvme zill what type of increase in fsync do you think i would be getting?
 
if i added an nvme zill what type of increase in fsync do you think i would be getting?
That depends in the end on the type of workload your VMs will produce. But the reviews on the Intel Optane show a good 4k seq write.
 
mostly data storage but there is 2 web portals hosted and 1 shared mysql database. and the typical DC and windows VMs for virtual desktops. only about 5 of those though.

and i push backups regularly so for the main VM store i am more interested in performance, it is on a zfs mirror just as a 'can't hurt' scenario.

would a 16gb optane be enough for the slog from the 1tb mirror or would a 32gb optane be best?

thanks for the help.
 
would a 16gb optane be enough for the slog from the 1tb mirror or would a 32gb optane be best?
If you have the choice of those two, then why not just go for the bigger?
 
actually based on IOPS i am looking at going with the 58gb.
it is substantially faster for not much more coin.
 
would it be worth reloading proxmox onto the optane and setting up a 32gb partition for SLOG and JUST hosting VMs off the SSD zfs mirror?
 
Last edited:

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!