Does RAID 0 increase I/O for VMs & Containers ?

moxfan

Active Member
Aug 28, 2013
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Hi,

My tests on bare metal servers show that read and write operations are a third faster with RAID 0 compared to RAID 1. The question is: Would that boost in I/O speed get reflected inside VMs and LXCs?
 
RAID 0 does not provide any redundancy. So while faster, It does not protect you from data loss.
That is why many people use RAID10, which combines the advantages of RAID 0 and RAID 1.
 
RAID1 can handle more read IOPS, RAID0 can also handle more write IOPS. I went from one disk (which ZFS also calls RAID0) to RAID1 and then to RAID10. I have not really noticed the speed inside a VM (like my desktop, its quick enough) but snapshot backups in the background of all VMs did get a lot faster.
What I remember that helped me most (when using 1 or 2 drives) was a ZFS pool for the host separate from the VMs and containers. A busy VM would sometimes slow down the host or vice versa (and the Proxmox filesystem does not need to be very fast). This was with version 3 or 4. I don't know if this still applies.
 
I am speculating you only have 2 disks so are limited in your options, if you really must use raid0, then make sure you do backups, a storage failure will happen sooner or later.