It is also important to note that there is wasted space with ZFS as is
right now if you use advanced format drives (usually 2TB or larger).
When using ashift=12 (4k sector size) to create a ZFS raid, you'll lose
about 10-20% of your disk capacity with ZFS depending on the RAID type,
I don't remember if this affects stripes or not. It is most noticeable
in my testing on a RAIDZ2. When using ashift=9 (512 sector size),
you'll have the full capacity but performance will suffer on advanced
format drives.
I've also opened up a performance bug about the write performance and
amount of data written to the devices far exceeding the initial write
size which seems to be pretty noticeable when your writes don't align
perfectly with the zfs block size. I had an email with you about this.
However, there are a lot of useful features in ZFS that may, or may not,
be worth this capacity loss and write performance limitations depending
on your use case. I have hopes the performance issues are being worked
out with the upcoming releases.
Pavel Odintsov <mailto:pavel.odint...@gmail.com>
Friday, January 9, 2015 3:39 PM
Hello, everybody!
Do somebody have any news about ZFS and OpenVZ experience?
Why not?
Did you checked my comparison table for simfs vs ploop vs ZFS volumes?
You should do it ASAP:
https://github.com/pavel-odintsov/OpenVZ_ZFS/blob/master/openvz_storage_backends.md
Still not interesting?
For example if you have 5Tb disk array (used up to 90%) and using
ploop now you lose about 800GB of disk space!
This data is from real HWN with few hundreds of containers.
I have excellent experience and very good news about ZFS! ZFS on Linux
team will add very important feature, linux quota inside container
(more details here https://github.com/zfsonlinux/zfs/pull/2577
But still no news about ZFS from OpenVZ team (and even from Virtuozza
Core) and we can work separately :)
Fortunately, we do not need any support from vzctl and can use "raw
vzctl" with some lightweight manuals from my repo:
https://github.com/pavel-odintsov/OpenVZ_ZFS/blob/master/OpenVZ_containers_on_zfs_filesystem.md
I collected all useful information here
https://github.com/pavel-odintsov/OpenVZ_ZFS
Stay tuned! Join to us!
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