Well, look at it this way: with 3X replication, for each TB of data you need 3 TB disk. With (for example) 10+3 EC, you get better protection, and for each TB of data you need 1.3 TB disk. -don- -----Original Message----- From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Loic Dachary Sent: 21 January, 2015 15:18 To: Chad William Seys; ceph-users@xxxxxxxxxxxxxx Subject: Re: erasure coded pool why ever k>1? On 21/01/2015 22:42, Chad William Seys wrote: > Hello all, > What reasons would one want k>1? > I read that m determines the number of OSD which can fail before > loss. But I don't see explained how to choose k. Any benefits for choosing k>1? The size of each chunk is object size / K. If you have K=1 and M=2 it will be the same as 3 replicas with none of the advantages ;-) Cheers -- Loïc Dachary, Artisan Logiciel Libre ---------------------------------------------------------------------- The information contained in this transmission may be confidential. Any disclosure, copying, or further distribution of confidential information is not permitted unless such privilege is explicitly granted in writing by Quantum. Quantum reserves the right to have electronic communications, including email and attachments, sent across its networks filtered through anti virus and spam software programs and retain such messages in order to comply with applicable data security and retention requirements. Quantum is not responsible for the proper and complete transmission of the substance of this communication or for any delay in its receipt. _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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