Hi guys, I'm interesting in the question, which setup will be faster:
a) a pool with journals on separate SSD's, OSD's on normal disks OR
b) a caching pool with SSDs only (osd+journal) in front
of a normal pool (osd+journal on normal disks)
A normal setup could be like this:
- 5-node firefly ceph-cluster, 6x spinner OSD and 2x SSD OSD each node.
- all pools have 3 replicates, no Erasure encoding.
Let's assume,
- Ethernet and SSDs are not the bottleneck (e.g. 10GBit Ethernet and fast SSDs)
- the SSD caching pool must be flushed as soon as possible (always <80% usage)
- the caching pool size is big enough (e.g. 10% of normal pool) to handle the
existing workload.
Existing workload could mean
1) to have sometime peak load on a bunch of KVM's
(e.g. Database operations and file copy operations)
2) running fio benchmark against a rbd device (which is smaller than the
caching pool).
Maybe somebody can tell me his 2 cents opinion what's the faster/better
solution? a) or b)
best regards
Daniel
smime.p7s
Description: S/MIME cryptographic signature
_______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
