I am looking to go virtual, I obviously would like to keep durability up and power usage down. I plan on getting a SSD to hold the virtual machines on. Can you keep the iso's stored on unRaid? Am I going to see a benefit from the more expensive SSD that are more high end as far as data transfer rates? Is the speed increase going to be noticeable? How big of a SSD do you recommend? I plan on the SSD to hold host os OpenSUSE with KVM from grumpy's tutorial with unraid, windows, pfsense, centos, and ubuntu virtual machines. I was thinking a 256GB SSD would be enough. Am I way off target? Any other suggestions? Thanks!

256GB is plenty for your VM store.  I have over 30 VM's and they total ~ 750GB ... but with only a half dozen or so you won't come close to filling a 256GB drive.

 

A good Intel or Crucial unit is all you need ... they'll provide all the bandwidth you need (and then some).

 

 

 

Thanks Gary!

Don't know which Hypervisor you are using but be sure to enable trim support for all the partitions and LVMs.

 

I also use noatime as well. Increases speed and less writes to SSD (which cuts into SSD lifespan).

 

Using this flag in one's /etc/fstab halts the logging of read accesses to the file system via an update to the atime information associated with the file. The importance of the noatime setting is that it eliminates the need by the system to make writes to the file system for files which are simply being read.

 

Note: Reiser (what unRAID uses) and even Reiser4 do not have trim support.

 

 

is this suitable for a trim cron script in Arch/Xen?

 

#!/bin/sh

# Trim / and /home file systems
date >> /var/log/trim.log
fstrim -v / >> /var/log/trim.log
fstrim -v /home >> /var/log/trim.log
exit 0

 

Also how do you enable noatime in a xen file system?

 

 

Thanks

Myk

r.e. TRIM support.    While it's nice to have ... and certainly ensures that the SSD has current garbage collection at all times; most modern SSDs do a very good job of garbage collection even without TRIM as long as there are ample amounts of "idle time" (i.e. no disc access).    They work fine even on older OS's (e.g. XP) without TRIM support -- which wasn't true with earlier SSDs.

 

In typical UnRAID usage there's plenty of idle time.  Whether that's true when you are also running a few VMs depends on what those VMs are doing ... but in most cases I'd think it's true then as well.    In other words, I wouldn't be overly concerned about TRIM support, or the lack thereof.