On 10/10/23 08:48, Damien Le Moal wrote:
On 10/9/23 15:15, Hannes Reinecke wrote:
On 10/9/23 02:56, charlesfdotz@xxxxxxxxxxxx wrote:
Hello,
I would like to request a new device manager layer be added that accepts
trim requests for sectors and instead writes zeros to those sectors.
This would be useful to deal with SMR (shingled magnetic recording) drives
that do not support trim. Currently after an SMR drive has had enough data
written to it the performance drops dramatically because the disk must
shuffle around data as if it were full and without trim support there is no
way to inform the disk which sectors are no longer used. Currently there's
no way to "fix" or reset this without doing an ATA secure erase despite
many of these disk being sold without informing customers that they were
SMR drives (western digital was sued for selling SMR drives as NAS
drives).
Gosh, no, please don't. SMR drives have a write pointer, and if the zone
needs to be reset you just reset the write pointer. Writing zeroes will
result in the opposite; the zone continues to be full, and no writes can
happen there.
Yes. And zone reset *is* a trim also since after a zone reset, the sectors in
the zone cannot be read.
On the same vein: why didn't we hook up 'wp reset' to trim/unmap?
The code says:
if (sd_is_zoned(sdkp)) {
sd_config_discard(sdkp, SD_LBP_DISABLE);
return count;
}
I distinctly remember to enable discards via 'wp reset' in the
original code; what happened to it?
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
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