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<p style="margin: 0 0 1em 0; color: black;">You attach the ssd as a hot
tier with a gluster command. I don't think that gdeploy or ovirt gui can do
it.</p>
<p style="margin: 0 0 1em 0; color: black;">The gluster docs and redhat
docs explains tiering quite good.</p>
<p style="margin: 0 0 1em 0; color: black;">/Johan</p>
</div>
<div style="color: black;">
<p
style="color: black; font-size: 10pt; font-family: Arial, sans-serif; margin: 10pt 0;">On
August 8, 2017 07:06:42 Moacir Ferreira <moacirferreira@hotmail.com>
wrote:</p>
<blockquote type="cite" class="gmail_quote"
style="margin: 0 0 0 0.75ex; border-left: 1px solid #808080; padding-left: 0.75ex;">
<div id="divtagdefaultwrapper"
style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;"
dir="ltr">
<p>Hi Devin,</p>
<p><br>
</p>
<p>Please consider that for the OS I have a RAID 1. Now, lets say I use
RAID 5 to assemble a single disk on each server. In this case, the SSD will
not make any difference, right? I guess that to be possible to use it, the
SSD should not be part of the RAID
5. In this case I could create a logical volume made of the RAIDed brick
and then extend it using the SSD. I.e.: Using gdeploy:</p>
<p><br>
</p>
<p>[disktype]</p>
<p>jbod</p>
<p>....</p>
<p>[pv1]</p>
<p>action=create</p>
<p>devices=sdb, sdc</p>
<p>wipefs=yes</p>
<p></p>
<p>ignore_vg_erros=no<br>
</p>
<p><br>
</p>
<p></p>
<p>[vg1]</p>
<p><b>action=create</b></p>
<p>vgname=gluster_vg_jbod</p>
<p>pvname=sdb</p>
<p>ignore_vg_erros=no<br>
</p>
<p><br>
</p>
<p>[vg2]</p>
<p><b>action=extend</b></p>
<p>vgname=gluster_vg_jbod</p>
<p>pvname=sdc</p>
<p>ignore_vg_erros=no<br>
</p>
<br>
<p>But will Gluster be able to auto-detect and use this SSD brick for
tiering? Do I have to do some other configurations? Also, as the VM files
(.qcow2) are quite big will I benefit from tiering? This is wrong and my
approach should be other?</p>
<p><br>
</p>
<p>Thanks,</p>
<p>Moacir<br>
</p>
<p><br>
</p>
<br>
<div style="color: rgb(49, 55, 57);">
<hr tabindex="-1" style="display:inline-block; width:98%">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b> Devin Acosta
<devin@pabstatencio.com><br>
<b>Sent:</b> Monday, August 7, 2017 7:46 AM<br>
<b>To:</b> Moacir Ferreira; users@ovirt.org<br>
<b>Subject:</b> Re: [ovirt-users] Good practices</font>
<div> </div>
</div>
<div>
<div id="bloop_customfont" style="color:rgb(0,0,0); margin:0px"><font
face="Input Mono"><br>
</font></div>
<div id="bloop_customfont" style="color:rgb(0,0,0); margin:0px"><font
face="Input Mono">Moacir,</font></div>
<div id="bloop_customfont" style="color:rgb(0,0,0); margin:0px"><font
face="Input Mono"><br>
</font></div>
<div id="bloop_customfont" style="color:rgb(0,0,0); margin:0px"><font
face="Input Mono">I have recently installed multiple Red Hat Virtualization
hosts for several different companies, and have dealt with the Red Hat
Support Team in depth about optimal configuration
in regards to setting up GlusterFS most efficiently and I wanted to share
with you what I learned.</font></div>
<div id="bloop_customfont" style="color:rgb(0,0,0); margin:0px"><font
face="Input Mono"><br>
</font></div>
<div id="bloop_customfont" style="color:rgb(0,0,0); margin:0px"><font
face="Input Mono">In general Red Hat Virtualization team frowns upon using
each DISK of the system as just a JBOD, sure there is some protection by
having the data replicated, however, the
recommendation is to use RAID 6 (preferred) or RAID-5, or at least RAID-1
at the very least.</font></div>
<div id="bloop_customfont" style="color:rgb(0,0,0); margin:0px"><font
face="Input Mono"><br>
</font></div>
<div id="bloop_customfont" style="margin:0px"><font face="Input Mono">Here
is the direct quote from Red Hat when I asked about RAID and
Bricks:</font></div>
<div id="bloop_customfont" style="margin:0px"><font face="Input Mono"><i><br>
</i></font></div>
<div id="bloop_customfont" style="margin:0px"><font
face="Input Mono"><i>"A typical Gluster configuration would use RAID
underneath the bricks. RAID 6 is most typical as it gives you 2 disk
failure protection, but RAID 5 could be used too. Once you have the
RAIDed bricks, you'd then apply the desired replication on top of that.
The most popular way of doing this would be distributed replicated with 2x
replication. In general you'll get better performance with larger
bricks. 12 drives is often a sweet spot. Another
option would be to create a separate tier using all
SSD’s.” </i></font></div>
<div id="bloop_customfont" style="margin:0px"><br>
</div>
<div id="bloop_customfont" style="margin:0px"><font face="Input Mono"><i>In
order to SSD tiering from my understanding you would need 1 x NVMe
drive in each server, or 4 x SSD hot tier (it needs to be distributed,
replicated for the hot tier if not using NVME).
So with you only having 1 SSD drive in each server, I’d suggest maybe
looking into the NVME option. </i></font></div>
<div id="bloop_customfont" style="margin:0px"><font face="Input Mono"><i><br>
</i></font></div>
<div id="bloop_customfont" style="margin:0px"><font
face="Input Mono"><i>Since your using only 3-servers, what I’d probably
suggest is to do (2 Replicas + Arbiter Node), this setup actually
doesn’t require the 3rd server to have big drives at all as it only
stores meta-data about the files and not actually a full
copy. </i></font></div>
<div id="bloop_customfont" style="margin:0px"><font face="Input Mono"><i><br>
</i></font></div>
<div id="bloop_customfont" style="margin:0px"><font
face="Input Mono"><i>Please see the attached document that was given to me
by Red Hat to get more information on this. Hope this information helps
you.</i></font></div>
<div id="bloop_customfont" style="margin:0px"><font face="Input Mono"><i><br>
</i></font></div>
<br>
<div id="bloop_sign_1502087376725469184" class="bloop_sign"><span
style="font-family:'helvetica Neue',helvetica; font-size:14px">--</span><br
style="font-family:'helvetica Neue',helvetica; font-size:14px">
<div class="gmail_signature"
style="font-family:'helvetica Neue',helvetica; font-size:14px">
<div dir="ltr">
<div><br>
</div>
<div>Devin Acosta, RHCA, RHVCA</div>
<div>Red Hat Certified Architect</div>
<div></div>
</div>
</div>
</div>
<br>
<p class="airmail_on">On August 6, 2017 at 7:29:29 PM, Moacir Ferreira (<a
href="mailto:moacirferreira@hotmail.com">moacirferreira@hotmail.com</a>)
wrote:</p>
<blockquote type="cite" class="clean_bq"><span>
<div dir="ltr">
<div></div>
<div>
<div id="divtagdefaultwrapper" dir="ltr"
style="font-size:12pt; color:#000000; font-family:Calibri,Helvetica,sans-serif">
<p><span>I am willing to assemble a oVirt "pod", made of 3
servers, each with 2 CPU sockets of 12 cores, 256GB RAM, 7 HDD 10K, 1 SSD.
The idea is to use GlusterFS to provide HA for the VMs. The 3 servers have
a dual 40Gb NIC and a dual 10Gb NIC. So my intention
is to create a loop like a server triangle using the 40Gb NICs for
virtualization files (VMs .qcow2) access and to move VMs around the pod
(east /west traffic) while using the 10Gb interfaces for giving services to
the outside world (north/south traffic).</span></p>
<p><br>
</p>
<p>This said, my first question is: How should I deploy GlusterFS in such
oVirt scenario? My questions are:</p>
<p><br>
</p>
<p>1 - Should I create 3 RAID (i.e.: RAID 5), one on each oVirt node, and
then create a GlusterFS using them?</p>
<p>2 - Instead, should I create a JBOD array made of all server's disks?</p>
<p>3 - What is the best Gluster configuration to provide for HA while not
consuming too much disk space?<br>
</p>
<p>4 - Does a oVirt hypervisor pod like I am planning to build, and the
virtualization environment, benefits from tiering when using a SSD disk?
And yes, will Gluster do it by default or I have to configure it to do so?</p>
<p><br>
</p>
<p>At the bottom line, what is the good practice for using GlusterFS in
small pods for enterprises?<br>
</p>
<p><br>
</p>
<p>You opinion/feedback will be really appreciated!</p>
<p>Moacir<br>
</p>
</div>
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