4 ms·
The other interesting thing about modern data centre HDDs is they have a media cache which significantly accelerates synchronous random write IOPS - OOTB these
by dvanders 4y ago
The other interesting thing about modern data centre HDDs is they have a media cache which significantly accelerates synchronous random write IOPS - OOTB these drives get 75 IOPS with fio fsync=1 bs=4k randwrite, but with a WCE=0 they can do 400 IOPS.
So if your app is fsync heavy (such as Ceph) then you can switch on this media cache by setting the drive to write through mode (WCE=0).
SATA SSDs have a similar quirk.