Proxmox VE on a SSD

[Telesight]

I want to install Proxmox VE on a small (test)server with an SSD as system storage.
As far as I understand you must have TRIM functionality in your filesystem and your kernel, otherwise the SSD will have a performance drop after a while.

Proxmox VE 2 uses EXT4 that has TRIM functionality, but it uses kernel 2.6.32 thas not the TRIM functionality.

So in short, can I use Proxmox VE in combination with an SSD?

 

[dietmar]

Proxmox VE 2 uses EXT4 that has TRIM functionality, but it uses kernel 2.6.32 thas not the TRIM functionality.

Our kernel is based on the RHEL6 kernel, and supports TRIM.

 

[Telesight]

Our kernel is based on the RHEL6 kernel, and supports TRIM.

Thank you Dietmar for your answer.
That means that I can run Proxmox VE 2.x on a SSD, great!

 

[mmenaz]

And proxmox 2.0 is based on ext3, not 4, correct? I ask because I installed it as soon as available, and maybe you switched to ext4 for rc1 or (future) final?

 

[dietmar]

And proxmox 2.0 is based on ext3, not 4, correct?

You can install what you want (default is ext3).

see http://pve.proxmox.com/wiki/Quick_installation

 

[Telesight]

If you want to use a SSD, you need TRIM functionality and AFAK Ext4 has only TRIM functionality ...

 

[mmenaz]

Interesting, but I remember in the past you or tom telling that ext3 was providing much better performances. Is new ext4 and new kernel much better in 2.0? Is it possible to have in the wiki or documented somewhere your tests results, so one can make a choice based upon 'facts' and not feelings?
thanks a lot

 

[tom]

no one said that ext4 is now faster - we still use ext3 as default, also in the latest 2.0 rc1.

 

[Telesight]

A few things that I have done to use my SSD:

An SSD uses TRIM, so you need the Ext4 filesystem to make use of TRIM and also the SSD must be mounted with the right option (discard) and you can add some other usefull commands to optimize the use of the SSD:
cp /etc/fstab /etc/fstab.bak #make a backup of fstab
nano /etc/fstab
add to the line: UUID=9e04f12c-4447-4e69-b1a7-48160eecafac /boot ext4 discard,noatime,nodiratime 0 1
Add a new line to fstab:
tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0
Save fstab

 

[mechanicus]

I want to install Proxmox VE on a small (test)server with an SSD as system storage.

If it's only a test system, you don't need trim, because it's for only a short time.
If you want to use SSD's in a production system, you have to use a RAID Controller, and there is no chance to transfer the trim command through the controller.
I've run a server with Proxmox 1.9 on a raid 5 of five SSD's. Controller was an Areca ARC 1220 whith a very good performance first.
But after half a year the system is bucking and I went back to conventional sas drives.

 

[hisaltesse]

What are the exact issues that you ended up having with SSDs after half a year?
Could you please be more specific?

- Have you tried to take the SSD disks out one at the time and reformat them to see if they would get their performance back?

- What is the total capacity of your SSD-based raid 5 array and what is its proxmox utilization?

 

[mechanicus]

For example: After the login on my windows xp vm, a fresh started program is frozen for about 10 to 15 sec.. After this, all runs well. Same in some Linux vm's. The server is not rumnnig the whole day, from 20:00 to 6:00 he is down and reboot at 6:00.
Since 2 weeks i've transfer the vm's to an other server running sas-hd's and all is well. The server with ssd's is shut down and I want to do a secure erase. I'm not sure, if I use them once more.

 

[hisaltesse]

How many SSDs did you have in your RAID5 array?

 

[mechanicus]

Five 128 GB Kingston.

 

[hisaltesse]

- Do you remember the amount of disk space left in your array when you started experiencing problems?
- Was your controller using its cache or did you enable write through?

We are currently running an 8 disk RAID10 with Vertex 3 max iops, with LSI MegaRaid 9265-8i + FastPath.

So far we have no issue. But it is too early to give a full assessment. However this controller is optimized for SSD and High IOPS…

The first thing I would do is reformat each drive. You could pull each drive out, reformat, re-add to the array, let it rebuild then pull another drive etc...

 

[mechanicus]

I've not initialise the whole RAID5 volume, only 70%. How I see now, the server with the ssd's was set up in march 2010, it runs without problems for about 1 1/2 years.
You're right, the FastPath software optimized the communication between the SAS-Controller and the Sandforce chip on the disk, it's very recommended.
I try it once more, but with new drives and a SATA3-megaraid controller and FastPath.