Hi Cephers, I've read about new BlueStore and have 2 questions:
1. The purpose of BlueStore is eliminating the drawbacks of POSIX when using FileStore. These drawbacks also cause journal, result in double write penalty. Could you explain me more detail about POSIX fails when using in FileStore? and how Bluestore still guarantee consistency without journal? I find a topic on reddit that told by journal, ceph avoid buffer cache, is it true? is is drawback of POSIX? https://www.reddit.com/r/ceph/comments/5wbp4d/so_will_ bluestore_make_ssd_journals_pointless/ 2. We have to put journal on SSD to avoid double write, but it lead to losing some OSDs when SSD fails. With BlueStore model, we can put all WAL, metadata, data on 1 disk, make it easily for monitoring, maintaining. But according to this post of Sebastian Han: https://www.sebastien-han.fr/blog/2016/05/04/Ceph-Jewel- configure-BlueStore-with-multiple-devices/ We could put WAL, metadata, and data on separate disks for increasing performance, I think it is not different to FileStore model. What is OSD deployment is most optimized? Put all on 1 disk or split on multi disks? Thanks in advance
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