Hi Norman On Wed, Mar 3, 2021 at 2:47 AM Norman.Kern <norman.kern@xxxxxxx> wrote: > James, > > Can you tell me what's the hardware config of your bcache? I use the 400G > SATA SSD as cache device and > > 10T HDD as the storage device. Hardware relationed? > It might be - all of the deployments I've seen/worked with use NVMe SSD devices and some more recent ones have used NVMe attached Optane devices as well (but that is usual). Backing HDD's are SAS attached 12TB ish 7K spinning disks. > > On 2021/3/2 下午4:49, James Page wrote: > > Hi Norman > > > > On Mon, Mar 1, 2021 at 4:38 AM Norman.Kern <norman.kern@xxxxxxx> wrote: > > > >> Hi, guys > >> > >> I am testing ceph on bcache devices, I found the performance is not > good > >> as expected. Does anyone have any best practices for it? Thanks. > >> > > I've used bcache quite a bit with Ceph with the following configuration > > options tweaked > > > > a) use writeback mode rather than writethrough (which is the default) > > > > This ensures that the cache device is actually used for write caching > > > > b) turn off the sequential cutoff > > > > sequential_cutoff = 0 > > > > This means that sequential writes will also always go to the cache device > > rather than the backing device > > > > c) disable the congestion read and write thresholds > > > > congested_read_threshold_us = congested_write_threshold_us = 0 > > > > The following repository: > > > > https://git.launchpad.net/charm-bcache-tuning/tree/src/files > > > > has a python script and systemd configuration todo b) and c) > automatically > > on all bcache devices on boot; a) we let the provisioning system take > care > > of. > > > > HTH > > > > > >> _______________________________________________ > >> 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 > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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