Never *ever* use nobarrier with ceph under *any* circumstances. I cannot stress this enough. -Sam On Fri, Nov 18, 2016 at 10:39 AM, Craig Chi <craigchi@xxxxxxxxxxxx> wrote: > Hi Nick and other Cephers, > > Thanks for your reply. > >> 2) Config Errors >> This can be an easy one to say you are safe from. But I would say most >> outages and data loss incidents I have seen on the mailing >> lists have been due to poor hardware choice or configuring options such as >> size=2, min_size=1 or enabling stuff like nobarriers. > > I am wondering the pros and cons of the nobarrier option used by Ceph. > > It is well known that nobarrier is dangerous when power outage happens, but > if we already have replicas in different racks or PDUs, will Ceph reduce the > risk of data lost with this option? > > I have seen many performance tuning articles providing nobarrier option in > xfs, but there are not many of then mention the trade-off of nobarrier. > > Is it really unacceptable to use nobarrier in production environment? I will > be much grateful if you guys are willing to share any experiences about > nobarrier and xfs. > > Sincerely, > Craig Chi (Product Developer) > Synology Inc. Taipei, Taiwan. Ext. 361 > > On 2016-11-17 05:04, Nick Fisk <nick@xxxxxxxxxx> wrote: > >> -----Original Message----- >> From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of >> Pedro Benites >> Sent: 16 November 2016 17:51 >> To: ceph-users@xxxxxxxxxxxxxx >> Subject: how possible is that ceph cluster crash >> >> Hi, >> >> I have a ceph cluster with 50 TB, with 15 osds, it is working fine for one >> year and I would like to grow it and migrate all my old > storage, >> about 100 TB to ceph, but I have a doubt. How possible is that the cluster >> fail and everything went very bad? > > Everything is possible, I think there are 3 main risks > > 1) Hardware failure > I would say Ceph is probably one of the safest options in regards to > hardware failures, certainly if you start using 4TB+ disks. > > 2) Config Errors > This can be an easy one to say you are safe from. But I would say most > outages and data loss incidents I have seen on the mailing > lists have been due to poor hardware choice or configuring options such as > size=2, min_size=1 or enabling stuff like nobarriers. > > 3) Ceph Bugs > Probably the rarest, but potentially the most scary as you have less > control. They do happen and it's something to be aware of > > How reliable is ceph? >> What is the risk about lose my data.? is necessary backup my data? > > Yes, always backup your data, no matter solution you use. Just like RAID != > Backup, neither does ceph. > >> >> Regards. >> Pedro. >> _______________________________________________ >> 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 > > > > > Sent from Synology MailPlus > _______________________________________________ > 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
 |