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Hi Guys, sorry for the late reply, my attention tends to be somewhat
sporadic due to work and the large number of rescue dogs/cats I care
for :)<br>
<br>
<div class="moz-cite-prefix">On 3/12/2015 8:34 PM, Krutika Dhananjay
wrote:<br>
</div>
<blockquote
cite="mid:1081929153.14542858.1449138875431.JavaMail.zimbra@redhat.com"
type="cite">
<div>We would love to hear from you on what you think of the
feature and where it could be improved.<span style="color:
#000000; font-family: nimbus-sans; font-size: 12px;
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<div>Specifically, the following are the questions we are seeking
feedback on:<br>
</div>
<div>a) your experience testing sharding with VM store use-case -
any bugs you ran into, any performance issues, etc<br>
</div>
</blockquote>
<br>
Testing was initially somewhat stressful as I regularly encountered
file corruption. However I don't think that was due to bugs, rather
incorrect settings for the VM usecase. Once I got that sorted out it
has been very stable - I have really stressed failure modes we run
into at work - nodes going down while heavy writes were happening.
Live migrations during heals. gluster software being killed while VM
were running on the host. So far its held up without a hitch.<br>
<br>
To that end, one thing I think should be made more obvious is the
settings required for VM Hosting:<br>
<br>
<blockquote>
<pre>quick-read=off
read-ahead=off
io-cache=off
stat-prefetch=off
eager-lock=enable
remote-dio=enable
quorum-type=auto
server-quorum-type=server</pre>
</blockquote>
They are quite crucial and very easy to miss in the online docs.
And they are only recommended with noo mention that you will corrupt
KVM VM's if you live migrate them between gluster nodes without them
set. Also the virt group is missing from the debian packages.<br>
<br>
Setting them does seem to have slowed sequential writes by about 10%
but I need to test that more.<br>
<br>
<br>
Something related - sharding is useful because it makes heals much
more granular and hence faster. To that end it would be really
useful if there was a heal info variant that gave a overview of the
process - rather than list the shards that are being healed, just a
aggregate total, e.g.<br>
<br>
$ gluster volume heal datastore1 status<br>
volume datastore1<br>
- split brain: 0<br>
- Wounded:65<br>
- healing:4<br>
<br>
It gives one a easy feeling of progress - heals aren't happening
faster, but it would feel that way :)<br>
<br>
<br>
Also, it would be great if the heal info command could return
faster, sometimes it takes over a minute.<br>
<br>
Thanks for the great work,<br>
<br>
Lindsay<br>
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