On 24 Aug 2019, at 14:01, Wesley Peng <weslepeng(a)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(a)ceph.io To unsubscribe send an email to ceph-users-leave(a)ceph.io

het volgende geschreven: 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 <weslepeng(a)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?

Op 24 aug. 2019 om 16:36 heeft Darren Soothill <darren.soothill@suse.com<mailto:darren.soothill@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?

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 _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io<mailto:ceph-users@ceph.io> To unsubscribe send an email to ceph-users-leave@ceph.io<mailto:ceph-users-leave@ceph.io>

No, they don’t. Imagine you take a machine down for maintenance and while that machine is down you loose a disk. You lost data. Although you can bring back the other machine you are still missing transactions. This is not fictional, this happens.