...@cern.ch, James Harper
ja...@ejbdigital.com.au
Cc: ceph-users@lists.ceph.com ceph-users@lists.ceph.com
Subject: Re: [ceph-users] Using large SSD cache tier instead of SSD
journals?
Message-ID:
c8c8e269282a034ca2a0180cbe01c24001b62...@wdcsrv.wdc.wigner.mta.hu
Content
Hi,
Consider a ceph cluster with one IO intensive pool (e.g. VM storage) plus a few
not-so IO intensive.
I'm thinking of whether it makes sense to use the available SSDs in the cluster
nodes (1 SSD for 4 HDDs) as part of a writeback cache pool in front of the IO
intensive pool, instead of
I'm thinking of whether it makes sense to use the available SSDs in the
cluster nodes (1 SSD for 4 HDDs) as part of a writeback cache pool in front of
the IO intensive pool, instead of using them as journal SSDs? With this
method, the OSD journals would be co-located on the HDDs or the SSD:HDD
-
From: James Harper [mailto:ja...@ejbdigital.com.au]
Sent: Tuesday, July 08, 2014 10:17 AM
To: Somhegyi Benjamin; ceph-users@lists.ceph.com
Subject: RE: Using large SSD cache tier instead of SSD journals?
Have you considered bcache? It's in the kernel since 3.10 I think.
It would
Hi Benjamin,
Unless I misunderstood, I think the suggestion was to use bcache devices on the
OSDs
(not on the clients), so what you use it for in the end doesn’t really matter.
The setup of bcache devices is pretty similar to a mkfs and once set up, bcache
devices
come up and can be mounted as
Hi James,
Yes, I've checked bcache, but as far as I can tell you need to manually
configure and register the backing devices and attach them to the cache
device, which is not really suitable to dynamic environment (like RBD devices
for cloud VMs).
You would use bcache for the osd not the
Wiebalck [mailto:arne.wieba...@cern.ch]
Sent: Tuesday, July 08, 2014 11:27 AM
To: Somhegyi Benjamin
Cc: ceph-users@lists.ceph.com
Subject: Re: [ceph-users] Using large SSD cache tier instead of SSD journals?
Hi Benjamin,
Unless I misunderstood, I think the suggestion was to use bcache devices
