Hi, do you want to hear the truth from real experience? Or the myth? The truth is that: - hdd are too slow for ceph, the first time you need to do a rebalance or similar you will discover... - if you want to use hdds do a raid with your controller and use the controller BBU cache (do not consider controllers with hdd cache), and present the raid as one ceph disk. - enabling single hdd write cache (that is not battery protected) is far worse than enabling controller cache (which I assume is always protected by BBU) - anyway the best thing for ceph is to use nvme disks. Mario Il giorno gio 6 apr 2023 alle ore 13:40 Marco Gaiarin < gaio@xxxxxxxxxxxxxxxxx> ha scritto: > > We are testing an experimental Ceph cluster with server and controller at > subject. > > The controller have not an HBA mode, but only a 'NonRAID' mode, come sort > of > 'auto RAID0' configuration. > > We are using SSD SATA disks (MICRON MTFDDAK480TDT) that perform very well, > and SAS HDD disks (SEAGATE ST8000NM014A) that instead perform very bad > (particulary, very low IOPS). > > > There's some hint for disk/controller configuration/optimization? > > > Thanks. > > -- > Io credo nella chimica tanto quanto Giulio Cesare credeva nel caso... > mi va bene fino a quando non riguarda me :) (Emanuele Pucciarelli) > > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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