Thanks for your answers; mine are inline, too. Le 02/06/2015 15:17, Eneko Lacunza a écrit : > 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? Yes, All DCS3700, for the four nodes. 16GB of RAM on this node. >> - 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. > Yes, confirmed by the thread "SSD DIsk Distribution". > 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. Agree; let's go apart from tiering and use journals only.
>> 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. Ok, i'll keep that in mind too. Thanks > > Cheers > Eneko > > _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
