On 07/22/2013 11:26 AM, Chen, Xiaoxi wrote: > > > 发自我的 iPhone > > 在 2013-7-23，0:21，"Gandalf Corvotempesta" <gandalf.corvotempesta@xxxxxxxxx> 写道： > >> 2013/7/22 Chen, Xiaoxi <xiaoxi.chen@xxxxxxxxx>: >>> Imaging you have several writes have been flushed to journal and acked，but not yet write to disk. Now the system crash by kernal panic or power failure，you will lose your data in ram disk，thus lose data that assumed to be successful written. >> >> The same apply in case of journal failure with data still on it. >> Imagine an SSD journal with 50GB of data. If SSD fails, all datas are lost. >> >> The only difference is that RAM is volatile and subjected to kernel >> panics or power failure (I only have dual power server) but actuall >> RAM is *MUCH* more reliable than SSD. I've never seen a single RAM >> module (server grade) failed from the latest 5-6 year. > RAM is physically much more reliable than ssd,but when taking kernel/power failure into account, i would like to bet Ram disk is MUCH dangerous than ssd I have not yet had the opportunity to try one, but something like the Marvell Dragonfly might be a very interesting option for servers with 24+ drives: https://origin-www.marvell.com/storage/dragonfly/nvram/ Mark > _______________________________________________ > 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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