TRIM support in drivers and dm/md?
Good morning,
Do many of the SATA controllers support TRIM? (i.e. pass the TRIM command to the SSD). Does anyone know anything about dm/md supporting TRIM? (I'm thinking LVM and software RAID tools).
Thanks!
Jeff
Quoted 4 lines · Jeff Layton
Do many of the SATA controllers support TRIM? (i.e. pass the TRIM command to the SSD). Does anyone know anything about dm/md supporting TRIM? (I'm thinking LVM and software RAID tools).
As far as I know, there's nothing to be done in any SATA controller driver to support TRIM. It's just up to the drive whether it understands the command.
Not sure what the sate of play is with MD/DM and TRIM. It's a bit tricky because some SATA drives will return different garbage from TRIMmed sectors each time they're read. That can hamper a RAID-5/6 rebuild "somewhat".
Signature · 4 lines
Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."
Quoted 8 lines · Matthew Wilcox
Quoted 4 lines · Jeff Layton
Do many of the SATA controllers support TRIM? (i.e. pass the TRIM command to the SSD). Does anyone know anything about dm/md supporting TRIM? (I'm thinking LVM and software RAID tools).
As far as I know, there's nothing to be done in any SATA controller driver to support TRIM. It's just up to the drive whether it understands the command.
That's the rub. I've heard that many drivers don't understand the command. So I'm curious what drivers do and any experience anyone might have.
Thanks!
Quoted 7 lines · Jeff Layton
Quoted 5 lines · Matthew Wilcox
Quoted 4 lines · Jeff Layton
Do many of the SATA controllers support TRIM? (i.e. pass the TRIM command to the SSD). Does anyone know anything about dm/md supporting TRIM? (I'm thinking LVM and software RAID tools).
Quoted 7 lines
Quoted 3 lines
As far as I know, there's nothing to be done in any SATA controller driver to support TRIM. It's just up to the drive whether it understands the command.
That's the rub. I've heard that many drivers don't understand the command. So I'm curious what drivers do and any experience anyone might have.
Note the distinction between "drive" and "driver"... I agree with what Matthew says.
Jeff
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Do many of the SATA controllers support TRIM? (i.e. pass the TRIM command to the SSD). Does anyone know anything about dm/md supporting TRIM? (I'm thinking LVM and software RAID tools).
As far as I know, there's nothing to be done in any SATA controller driver to support TRIM. It's just up to the drive whether it understands the command.
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That's the rub. I've heard that many drivers don't understand the command. So I'm curious what drivers do and any experience anyone might have.
Note the distinction between "drive" and "driver"... I agree with what Matthew says.
Oops - sorry I missed "drive" vs. "driver".
I've heard from other places that drivers need to pass along the TRIM command to the drives but that many drivers don't do this. I assume that the best way to determine if this is accurate is to test the controller drivers or ping the maintainers.
Thanks!
Quoted 19 lines · Jeff Layton
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Do many of the SATA controllers support TRIM? (i.e. pass the TRIM command to the SSD). Does anyone know anything about dm/md supporting TRIM? (I'm thinking LVM and software RAID tools).
As far as I know, there's nothing to be done in any SATA controller driver to support TRIM. It's just up to the drive whether it understands
the command.Quoted 7 lines
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That's the rub. I've heard that many drivers don't understand the command. So I'm curious what drivers do and any experience anyone might have.
Note the distinction between "drive" and "driver"... I agree with what Matthew says.
Quoted 6 lines
Oops - sorry I missed "drive" vs. "driver".
I've heard from other places that drivers need to pass along the TRIM command to the drives but that many drivers don't do this. I assume that the best way to determine if this is accurate is to test the controller drivers or ping the maintainers.
I'd object to the words "many" and "drivers" :)
The general rule for all kernel SATA drivers is to support all ATA commands, including future, unknown commands not invented yet.
That's because kernel SATA drivers deal primarily with the sending/receiving from hardware an opaque data bundle -- the ATA taskfile -- rather than create a software system that requires new code in each driver, for each new ATA command.
That's the ideal and, if you obtained a SATA controller in the past 5 years or so, your controller (ahci, sata_sil24, others) supports TRIM just fine because it is a generic ATA taskfile transport and nothing more.
Some now-uncommon controllers have problems with new ATA commands, either due to (a) they are complex, firmware-driven RAID-esque beasts, or (b) they have an internal command table. And I imagine some early SATA<->PATA bridge chips probably get confused as well. But those are the minority, and getting less frequent by the day.
Note in all of the above I say "controller" rather than "driver". I know of no _driver_ that prevents TRIM, where the underlying controller hardware supports it.
For the controllers that don't support TRIM, the error behavior should be something predictable and consistent like a command abort.
Jeff
sata_sil didn't support trim the last time I checked (the hardware can do it though). sata_sil24 does, though, along with ahci, sata_mv, etc..
Cheers
Quoted 3 lines · Mark Lord
sata_sildidn't support trim the last time I checked (the hardware can do it though).sata_sil24does, though, along with ahci,sata_mv, etc..
The recent sata_mv bugfix should be noted of course...