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Solid State Drive

Posted: Thu Jun 21, 2012 5:28 pm
by bigfoot65
Anyone have advice on using an Solid State Drive in a server for virtualization? I am considering using a 120GB SSD with Proxmox.

I have read several articles on the internet that state using it for the OS only offers benefit of booting up the OS. Others have said to use it for storing the virtualization files, i.e. mounting it as /var/lib/vz.

I do understand that in order to get the TRIM I must use the ext4 file system and do some manual tweaks to prevent the SSD from getting pounded. Some say to turn off journaling and to set the tmp area to RAM.

Any advice would be greatly appreciated as I would like to move forward knowing I chose the right solution.

Re: Solid State Drive

Posted: Fri Jun 22, 2012 5:38 am
by sgtfoo
You won't be able to put huge volumes or drive images on it, but the OS and some of your more slow-loading OS images would benefit from it.

I run both Fedora 17 and wattOS from a SSD, and everytime I use an SSD, I
- definitely load the tmp to ram
- have lots of RAM (I have 8gb on both systems)
- a replace "defaults" with "discard,noatime,nodiratime" in the /etc/fstab for SSD-residing mounts, except the swap

ProxMox specifically..
- Proxmox won't let you change the swap on install AFAIK, but you can change it in the fstab after install
- It will auto-LVM in proxmox, so having other faster drives is a good idea otherwise some i/o delay may occur when lvm crosses over to the other drives from the SSD, if any OS or drive image files are across the gap
- note that the OpenVZ containers will only work within ext3 volumes
- Trim support was added for LVM in the 2.6.37 kernel but don't combine LVM and RAID as that would cancel out Trim.
- if it's a relatively new SSD I wouldn't worry about journaling being on or off. I haven't ever done so with any SSDs.
- Proxmox like many other Hypervisors create unique swap sections sometimes out of files. I haven't yet researched where and how they're created but it's the swap for the VMs that it creates if I'm not mistaken... those swap files are OK if they're born of linux VMs, but for Windows VMs I would suggest to keep those swaps outside the SSD.

- You might be able to save some cash and even use a smaller SSD for the exclusive Proxmox Install... somehting like a 40-60GB SSD.
I've got mine on a 74GB WD Raptor that a local garage sale had no idea was so valuable.

Re: Solid State Drive

Posted: Fri Jun 22, 2012 7:15 am
by bigfoot65
Thanks for the info. So am I to understand correctly that I can still format the SSD as ext4 and install Proxmox? I planned to move the swap file and tmp to RAM after install.

Also, I only use VMs and no containers, so will OpenVZ still work with this setup? I have searched all over the internet for a simple tutorial for installing Proxmox on SSD with little success.

It appears to be possible, but not a lot of good guidance on how to configure it. I will be using a 128GB SSD, so figure that would be fine for the 5 or 6 VMs that I currently utilize.

This setup is primarily used for Amahi testing and development, so I want to make it as quick and efficient as possible. I also plan to have a 500GB drive for storing VM snapshots and ISO files. Using a Dual Core processor with 8GB Ram at the moment to support this design.

I have limited knowledge and experience in this area, so any tips or advice is most welcome.

Re: Solid State Drive

Posted: Fri Jun 22, 2012 8:04 am
by sgtfoo
could you post the articles showing why it won't work?
I strongly doubt an SSD changes anything except for read/write counts. If anything I imagine there may be a slightly lesser lifespan of the drive, but that's to be expected.

If I'm not mistaken, Proxmox, upon install turns the main drive chosen, into an LVM volume and some of it not. The LVM part is for local storage on the drive until you add more drives to the LVM group, post-install. Don't power up any other drives during install except for your SSD. The non-LVM'd part of the install drive is for the Proxmox OS itself... a very clever way to seperate actually.

If you're using no OpenVZ containers, then all the partitions/images you create inside the storage LVM can be ext4. The storage part of the LVM group on the 120GB can be used for OS containers. You can configure storage any way you like, as long as the web GUI finds it.

Re: Solid State Drive

Posted: Sat Jun 23, 2012 6:44 am
by bigfoot65
I don't have any specific links, but the Proxmox forums lead me to believe it will not work. Most use cases are using 2 SSDs in a raid array. I only want to use the 1 drive for OS/VMs basically.

I am a bit disappointed in how Linux works with the SSD. It seems only the etx4 filesystem supports TRIM and there is a lot of tweaking to get the correct set up. Not sure what I am gonna do with it now, maybe add to a desktop box and use for a client system.

If you know of any good tutorials, it would be greatly appreciated. For now, I guess I will leave my Proxmox server using SATA drives.

Re: Solid State Drive

Posted: Sun Jun 24, 2012 8:28 am
by sgtfoo
All the tutorials and most of the users on the Proxmox forums are corporate-grade users that are using proxmox in a professional environment. The thing about virtualization as such a low level is that you need fast drives. Doing SSDs in a raid config for duplication is fair, but for speed/performance it's absurd.

Using SSD for the OS drive really is more straight forward than anyone is making it. The only parameters you really need to set are the "discard,noatime,nodiratime" in the fstab and that's all.

Just yesterday I finished re-configuring my Amahi server to run within my Proxmox setup. As the prices of SSDs goes down, I'm gonna replace my OS drive with an SSD and replace an image/container (guest OS) drive with an SSD as well.

It's really a no-brainer. Not much change of process or consideration need go into building a "sandbox" VE server unless you want 3 nodes for High Availability and absolutely ZERO i/o delay.

//2 cents

Re: Solid State Drive

Posted: Sun Jun 24, 2012 8:37 am
by bigfoot65
True. I was just looking for something to ensure I set things up correctly. I am using a 128GB SSD currently as a test HDA with Ubuntu. Once my test is done and I convert my F14 HDA to Ubuntu, I will put the SSD in the Proxmox server as the OS disk.

Althought 128GB is not big, it should be fine for what I do. I will keep all the ISOs and Backups on a SATA drive so the SSD does not fill up too quick.

Thanks for the advice and hope to report my success soon.