Bug 197715 - No TRIM with Samstung T5 external SSD
Summary: No TRIM with Samstung T5 external SSD
Status: NEW
Alias: None
Product: IO/Storage
Classification: Unclassified
Component: Other (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: io_other
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-11-02 22:38 UTC by Sven Köhler
Modified: 2020-01-12 04:48 UTC (History)
2 users (show)

See Also:
Kernel Version: 5.4.10
Subsystem:
Regression: No
Bisected commit-id:

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Description Sven Köhler 2017-11-02 22:38:01 UTC 
The Samsung T5 has a USB to SATA bridge with UAS. According to [1] it uses the ASMedia ASM235CM bridge chip.

I do not know whether the ASM235CM has proper support for TRIM (whatever that means) or it is only supported at the ATA pass-through level (which causes issue with command queuing I guess?).

Can TRIM be support with this sort of drive? Or will it remain unsupported?
fstrim fails for me with "the discard operation is not supported".


[1] https://www.anandtech.com/show/11719/samsung-portable-ssd-t5-review-64layer-vnand-debuts-in-retail
Comment 1 Sven Köhler 2017-11-08 23:44:04 UTC 
It is claimed at [2] that the UASP to SATA bridge must convert SCSI UNMAP to TRIM commands. I do not know, whether the ASM235CM used in the Samsung T5 supports that. Would Linux support fstrim on an UASP drive if UNMAP was supported?

Windows 10 has no problem to "optimize" (MS-equivalent of fstrim) the NTFS partition on my SSD while I cannot fstrim the ext4 partition on the SSD.

[2] https://blog.startech.com/post/all-you-need-to-know-about-uasp/
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