<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body dir="auto">
<div>Greetings,</div>
<div id="AppleMailSignature"><br>
</div>
<div id="AppleMailSignature">I just want to report that after a clean istall of r151020 I found a bug whereby importing an older zpool from r151012 and running zpool upgrade causes an SSD cache device size to be reported incorrectly. (only 1 out of 4 devices
in this instance)</div>
<div id="AppleMailSignature"><br>
</div>
<div id="AppleMailSignature">The cache device size is 93gb and arcstat reported it to be 680gb.</div>
<div id="AppleMailSignature"><br>
</div>
<div id="AppleMailSignature">I confirmed by monitoring zpool iostat -v and saw the same size being reported.</div>
<div id="AppleMailSignature"><br>
</div>
<div id="AppleMailSignature">We've had a lot of weird io lockups (which is how I found the issue, we didnt notice it until a month after) that brings all of our NFS mounts to a screeching halt and this was the only thing I could find to be out of the ordinary
on the system.</div>
<div id="AppleMailSignature"><br>
</div>
<div id="AppleMailSignature">CPU average @1% , 20% of ram free, no crazy processes waiting on IO. It was completely invisible. At least from my testing using several dtrace scripts from the net.</div>
<div id="AppleMailSignature"><br>
</div>
<div id="AppleMailSignature">I can only assume that the incorrect size reporting caused the zpool to fill the cache drive up beyond its physical capacity during periods of heavy load.</div>
<div id="AppleMailSignature"><br>
</div>
<div id="AppleMailSignature">I removed all cache devices and then added them back to the zpool. Then all disks reported correctly again. Format/diskinfo always reported correctly so it was specific to zfs.</div>
<div id="AppleMailSignature"><br>
</div>
<div id="AppleMailSignature">We're monitoring the NAS closely to see if the issues occur again. </div>
<div id="AppleMailSignature"><br>
<br>
<span style="font-size: 13pt;">John Barfield</span></div>
</body>
</html>