[ceph-users] Sizing for bluestore db and wal

Janne Johansson icepic.dz at gmail.com
Mon Nov 26 01:27:56 PST 2018


Den mån 26 nov. 2018 kl 10:10 skrev Felix Stolte <f.stolte at fz-juelich.de>:
>
> Hi folks,
>
> i upgraded our ceph cluster from jewel to luminous and want to migrate
> from filestore to bluestore. Currently we use one SSD as journal for
> thre 8TB Sata Drives with a journal partition size of 40GB. If my
> understanding of the bluestore documentation is correct, i can use a wal
> partition for the writeahead log (to decrease write latency, similar to
> filestore) and a db partition for metadata (decreasing write AND read
> latency/throughput). Now I have two questions:
>
> a) Do I really need an WAL partition if both wal and db are on the same SSD?

I think the answer is no here, if you point the DB to an SSD, bluestore will
use it for WAL also.

> b) If so, what would the ratio look like? 99% db, 1% wal?

..which means just let ceph handle this itself.

-- 
May the most significant bit of your life be positive.


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