If you have decent CPU and RAM on the OSD nodes, you can try Erasure Coding, even just 4:2 should keep the cost per GB/TB lower than 2:1 replica (as that's basically 1.5:1 for cost) and much safer (same protection as 3:1 replica). We use that on our biggest production SSD pool. ________________________________ From: Wesley Peng <weslep...@gmail.com> Sent: Sunday, 25 August 2019 9:11 PM To: Wido den Hollander <w...@42on.com> Cc: ceph-users@ceph.io <ceph-users@ceph.io> Subject: [ceph-users] Re: ceph's replicas question
Ok thanks. Wido den Hollander <w...@42on.com<mailto:w...@42on.com>>于2019年8月25日 周日上午4:47写道： > Op 24 aug. 2019 om 16:36 heeft Darren Soothill > <darren.sooth...@suse.com<mailto:darren.sooth...@suse.com>> het volgende > geschreven: > > So can you do it. > > Yes you can. > > Should you do it is the bigger question. > > So my first question would be what type of drives are you using? Enterprise > class drives with a low failure rate? > Doesn’t matter. From my experience: With 2x replication you will loose data at some point. As a consultant I have just seen too many cases of data loss with 2x. Please, don’t do it. > Then you have to ask yourself are you feeling lucky? > > If you do a scrub and 1 drive returns 1 value and another drive returns > another value which one is correct? > > What happens should you have a drive failure and you have any other error? A > node failure? Another disk failure? A disk read error? All of these could > mean data loss. > > How important is the data you are storing and do you have a backup of it as > you will need that backup at some point. > > Darren > > Sent from my iPhone > >> On 24 Aug 2019, at 14:01, Wesley Peng >> <weslep...@gmail.com<mailto:weslep...@gmail.com>> wrote: >> >> >> Hi, >> >> We have all SSD disks as ceph's backend storage. >> Consider the cost factor, can we setup the cluster to have only two replicas >> for objects? >> >> thanks & regards >> Wesley >> _______________________________________________ >> ceph-users mailing list -- ceph-users@ceph.io<mailto:ceph-users@ceph.io> >> To unsubscribe send an email to >> ceph-users-le...@ceph.io<mailto:ceph-users-le...@ceph.io> > _______________________________________________ > ceph-users mailing list -- ceph-users@ceph.io<mailto:ceph-users@ceph.io> > To unsubscribe send an email to > ceph-users-le...@ceph.io<mailto:ceph-users-le...@ceph.io>
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