[Gluster-users] GlusterFS for production use with Ovirt

[Paul Robert Marino]

A few things to clarify
1) are all 4 for Gluster or are they the whole cluster.
keep in mind that Ovirt expects that you are running Gluster on
different nodes than your VM's. while I do not completely agree with
that idea that is how it is now.

2) RAID hardware is not necessarily a bad thing, in fact the cache may
help significantly. that said  it is not required.
things to keep in mind if you are using RAID hardware for performance
2.a) RAID 0 will give you the best speed if you are using 3 nodes for
quorum. keep in mind this will require more work in the case of a
drive failure to remake the brick.
2.b) if you are only doing a mirror across 2 bricks RAID 0 may be
acceptable but consider using 1+0 or RAID 5 the performance on the two
may vary depending on the RAID controller but 1+0 is generally faster.
2.c) always optimize for the stripe which in theory should be
automatic if the RAID controller reports the required information to
do it, but in practice most do not so you should do it manually and
Red Hat's support site just added a nice tool to do it for you.

3) for performance more RAM is rarely a bad thing; however it can be
with sustained writes.If you are constantly writing faster than the
disks can handle you will eventually fill the buffers and block till
they flush. so the answer here is if you are mostly dealing with reads
more and bursts of writes more ram is better. if you are dealing with
constant writes it may cause uneven performance and may in fact be
detrimental.

4) On the 10Gb consider using consider using RDMA Iverbs over Ethernet
it may help.

5) Look closely at the scheduler on the disks the default these days
is CFQ (Completely Fair Queuing). I find DEADLINE works better for
Gluster; however depending on if you are using a RAID and you have a
properly aligned file system you may find NOOP may provide better
performance you need to do some testing with your hardware to
determine if this is the case.

On Mon, Mar 23, 2015 at 9:43 PM, Punit Dambiwal <hypunit at gmail.com> wrote:
> Hi,
>
> I want to use Glusterfs with Ovirt 3.5...please help me to make the
> architecture stable for the production use :-
>
> I have 4 servers...every server can host 24 SSD disk(As bricks)..i want to
> deploy distributed replicated storage with replica =2....i don't want to use
> the Hardware RAID...as i think it will badly impact the performance...
>
> 1. Glusterfs 3.5 or 3.6 ?? (which one will be stable for the production
> use).
> 2. Do i use the Hardware RAID or Not ??
> 3. IF HW RAID then which RAID level and does it impact the performance...
> 4. I want to make it rock solid...so it can use for production purpose...
> 5. How much RAM should be sufficient on each server...on the each server i
> have two E5 CPU's...
> 6. For Network Connectivity i have 2*10G NIC with bonding on each server...
>
> Thanks,
> Punit
>
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