On Thu, Dec 17, 2015 at 2:31 PM, Simon Hallam <sha@xxxxxxxxx> wrote: > Hi all, > > > > I’m looking at sizing up some new MDS nodes, but I’m not sure if my thought > process is correct or not: > > > > CPU: Limited to a maximum 2 cores. The higher the GHz, the more IOPS > available. So something like a single E5-2637v3 should fulfil this. No idea where you're getting the 2 core part. But a mid range CPU like the one you're looking at is probably perfectly appropriate. As you have probably gathered, the MDS will not make good use of large core counts (though there are plenty of threads and various serialisation/deserialisation parts can happen in parallel). > Memory: The more the better, as the metadata can be cached in RAM (how much > RAM required is dependent on number of files?). Correct, the more RAM you have, the higher you can set mds_cache_size, and the larger your working set will be. > HDD: This is where I’m struggling, does their speed/IOPs have an significant > impact on the performance of the MDS (I’m guessing this is dependent on if > the metadata fits within RAM)? If so, does the NVMe SSDs look like the right > avenue, or will standard SATA SSDs suffice? The MDS does not store anything on local drives. All the metadata is stored in RADOS (i.e. on the OSD nodes). All that goes locally is config files and debug logs. John > > > > Thanks in advance for your help! > > > > Simon Hallam > > > > Please visit our new website at www.pml.ac.uk and follow us on Twitter > @PlymouthMarine > > Winner of the Environment & Conservation category, the Charity Awards 2014. > > Plymouth Marine Laboratory (PML) is a company limited by guarantee > registered in England & Wales, company number 4178503. Registered Charity > No. 1091222. Registered Office: Prospect Place, The Hoe, Plymouth PL1 3DH, > UK. > > This message is private and confidential. If you have received this message > in error, please notify the sender and remove it from your system. You are > reminded that e-mail communications are not secure and may contain viruses; > PML accepts no liability for any loss or damage which may be caused by > viruses. > > > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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