[PVE-User] Ceph Journal Performance

[Dmitry Petuhov]

05.11.2014 3:52, Lindsay Mathieson пишет:
> Can journal size be too large? if I gave 20GB+ to a journal for 3TB drives would it be used or is that just a waste? thanks, 
Journal size is not matter of drive size, but of its speed and required write size/performance. It is amount of data that clients can write at SSD's speed before it is flushed to backing slow HDD.
With huge journals, you may want to tune 'filestore max sync interval' parameter in ceph.conf. See http://ceph.com/docs/master/rados/configuration/filestore-config-ref/