2009/7/13 Domas Mituzas <[email protected]>: >> Precis: if the file system is very busy (being hammered) *and* it's >> over 85% full, the block allocator can get stuck trying to work out >> the *very best* allocation rather than one that'll do and let it get >> on with other work. To the point where you see CPU go through the >> roof, with 80% system CPU and a very unresponsive system. You can't >> stop this without rebooting the box.
> This is exactly what we're seeing, except that we could get out of it > by dropping older snapshots. Yeah - cutting down how full the file system is. >> Sun acknowledged it as a bug and it'll be fixed in a future release; >> they gave us a hotpatch. The workaround? Keep the ZFS filesystem in >> question under 70% full ... > :-) > hehehehehe, 'the heck beaten out of it' sounds like what we tend to do > to our systems at wikimedia ;-) It's useful testing, and you can be sure Sun will be interested in your results in detail, we're a reasonably famous site! A coworker spoke to the Sun kernel engineer tearing his hair out over this one ... I fear the answer re: ZFS is to some extent "don't do that then" until it's fixed. Of course, you want snapshots. It's a tricky one. - d. _______________________________________________ Wikitech-l mailing list [email protected] https://lists.wikimedia.org/mailman/listinfo/wikitech-l
