On Fri, 18 Sep 2015 12:00:15 PM Duncan wrote: > The caveat here is that if the VM/DB is active during the backups (btrfs > send/receive or other), it'll still COW1 any writes during the existence > of the btrfs snapshot. If the backup can be scheduled during VM/DB > downtime or at least when activity is very low, the relatively short COW1 > time should avoid serious fragmentation, but if not, even only relatively > temporary snapshots are likely to trigger noticeable cow1 fragmentation > issues eventually.
One relevant issue for this is whether the working set of the database fits into RAM. RAM has been getting bigger and cheaper while databases I run haven't been getting bigger. Now every database I run has a working set that fits into RAM so read performance (and therefore fragmentation) doesn't matter for me except when rebooting - and database servers don't get rebooted that often. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
