-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 El 2021-01-28 a las 18:20 +0300, Andrei Borzenkov escribió:
28.01.2021 17:21, Per Jessen пишет:
No, harddisks generally have write cache disabled
Consumer hard disks generally have write cache enabled because it is good for benchmarks (and performance as perceived by users).
[ 1.894064] sd 1:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Telcontar:~ # journalctl | grep "Write cache" Jan 15 12:24:21 Telcontar kernel: sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 15 12:24:21 Telcontar kernel: sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 15 12:24:21 Telcontar kernel: sd 2:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 15 12:24:21 Telcontar kernel: sd 3:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 15 23:20:32 Telcontar kernel: sd 10:0:0:0: [sde] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA Jan 20 02:57:15 Telcontar kernel: sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 20 02:57:15 Telcontar kernel: sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 20 02:57:15 Telcontar kernel: sd 2:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 20 02:57:15 Telcontar kernel: sd 3:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 24 04:38:56 Telcontar kernel: sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 24 04:38:56 Telcontar kernel: sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 24 04:38:56 Telcontar kernel: sd 2:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Jan 24 04:38:56 Telcontar kernel: sd 3:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA No report on the nvme disk. Curious. sde had it disabled on Jan 15, then no report. Ah, must have been an external stick, I forgot. What are DPO or FUA? Tried googling the first, found "days past ovulation" as first hit. Then looked on wikipedia and saw nothing for computers. Similar bad luck for FUA.
They are not specifically made for raid - WDC used to have a series called "RAID edition", but I think they've stopped that.
They usually have different default settings (well known recovery timeout as example) and may have better quality control. HDD write cache is controlled by RAID controllers (which can explicitly enable or disable it or just leave it as is).
Software raid in Linux doesn't seem to do it. I have one raid 5 partition for playing. - -- Cheers, Carlos E. R. (from openSUSE 15.2 x86_64 at Telcontar) -----BEGIN PGP SIGNATURE----- iHoEARECADoWIQQZEb51mJKK1KpcU/W1MxgcbY1H1QUCYBMJxRwccm9iaW4ubGlz dGFzQHRlbGVmb25pY2EubmV0AAoJELUzGBxtjUfVtIUAn1RzKn4hTBqM1O7gj/KV sNYHTYleAJ9OVFRl5L3z63/jk5wz+GfvkFH5Dg== =Dqzh -----END PGP SIGNATURE-----