Hi,
On 02/06/15 14:51, Phil Schwarz wrote:
i'm gonna have to setup a 4-nodes Ceph(Proxmox+Ceph in fact) cluster.
-1 node is a little HP Microserver N54L with 1X opteron + 2SSD+ 3X 4TB SATA
It'll be used as OSD+Mon server only.
Are these SSDs Intel S3700 too? What amount of RAM?
- 3 nodes are setup upon Dell 730+ 1xXeon 2603, 48 GB RAM, 1x 1TB SAS
for OS , 4x 4TB SATA for OSD and 2x DCS3700 200GB intel SSD
I can't change the hardware, especially the poor cpu...
Everything will be connected through Intel X520+Netgear XS708E, as 10GBE
storage network.
This cluster will support VM (mostly KVM) upon the 3 R730 nodes.
I'm already aware of the CPU pegging all the time...But can't change it
for the moment.
The VM will be Filesharing servers, poor usage services (DNS,DHCP,AD or
OpenLDAP).
One Proxy cache (Squid) will be used upon a 100Mb Optical fiber with
500+ clients.
My question is :
Is it recommended to setup the 2 SSDS as :
One SSD as journal for 2 (up to 3in the future) OSDs
Or
One SSD as journal for the 4 (up to 6 in the future) OSDs and the
remaining SSD as cache tiering for the previous SSD+4 OSDs pool ?
I haven't used cache tiering myself, but others have not reported much
benefit from it (if any) at all, at least this is my understanding.
So I think it would be better to use both SSDs for journals. It probably
won't help performance using 2 instead of only 1, but it will lessen the
impact from a SSD failure. Also it seems that the consensus is 3-4 OSD
for each SSD, so it will help when you expand to 6 OSD.
SSD should be rock solid enough to support both bandwidth and living
time before being destroyed by the low amount of data that will be
written on it (Few hundreds of GB per day as rule of thumb..)
If all are Intel S3700 you're on the safe side unless you have lots on
writes. Anyway I suggest you monitor the SMART values.
Cheers
Eneko
--
Zuzendari Teknikoa / Director Técnico
Binovo IT Human Project, S.L.
Telf. 943575997
943493611
Astigarraga bidea 2, planta 6 dcha., ofi. 3-2; 20180 Oiartzun (Gipuzkoa)
www.binovo.es
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