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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">Hello Bob,<br>
<br>
We did something similar - our MDS's used zpools based on spinning disks in JBODs and we switched to SSDs without bringing the filesystem down, using ZFS to replicate data. It worked great for us.<br>
<br>
How are your pools organized (ie what does zpool status show)? There might be options that are more or less risky, or take more or less time, depending on how zfs is using the disks.<br>
<br>
Also, how often are disks failing and how long does a replacement take to resilver, with your current disks?<br>
<br>
-Olaf<br>
<br>
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<div id="divRplyFwdMsg"><font color="#000000" face="Tahoma" size="2"><b>From:</b> Bob Ball [ball@umich.edu]<br>
<b>Sent:</b> Monday, November 23, 2015 12:22 PM<br>
<b>To:</b> Faaland, Olaf P.; Morrone, Chris<br>
<b>Cc:</b> Bob Ball<br>
<b>Subject:</b> Expanding a zfsonlinux OST pool<br>
</font><br>
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<div>Hi,<br>
<br>
We have some zfsonlinux pools in use with Lustre 2.7 that use some older disks, and we are rapidly running out of spares for those. What we would _like_ to do, if possible, is replace all of those 750GB disks in an OST, one at a time with re-silver between,
with 1TB disks, then expand the OST when the last is complete to utilize the larger space and the more reliable disks.<br>
<br>
Is this going to work? One of us here found the following:<br>
<blockquote>
<pre>According to the Oracle docs, a pool can autoexpand if you set it to
do so. I think the default must be off because the one I checked is
off (but that does indicate support of the feature in the linux
release also).
<a class="moz-txt-link-freetext" href="http://docs.oracle.com/cd/E19253-01/819-5461/githb/index.html" target="_blank">http://docs.oracle.com/cd/E19253-01/819-5461/githb/index.html</a>
[root@umdist02 ~]# zpool get autoexpand ost-006
NAME PROPERTY VALUE SOURCE
ost-006 autoexpand off default
</pre>
</blockquote>
<pre>We are using zfsonlinux version 0.6.4.2. Can we follow the procedures outlined in the oracle doc using zfsonlinux?
I guess my initial question assumed the expansion would not happen until the last disk is added and re-silvered, but the document indicates this is not really necessary?
Thanks,
bob
</pre>
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