Re: Quick EXT4 discard question

[Keith Mannthey <kmannth@us.ibm.com>]

On Fri, 2011-04-22 at 09:44 +0200, Lukas Czerner wrote:
> On Fri, 22 Apr 2011, Tao Ma wrote:
> 
> > On 04/22/2011 10:44 AM, Keith Mannthey wrote:
> > > On Fri, 2011-04-22 at 10:27 +0800, Tao Ma wrote:
> > >> On 04/22/2011 08:45 AM, Keith Mannthey wrote:
> > >>> Hello,
> > >>>   I am using some Intel SSD drives with 2.6.38.2. 
> > >>>
> > >>>
> > >>> /proc/scsi/scsi identifies them as: 
> > >>>
> > >>> "
> > >>> Host: scsi4 Channel: 00 Id: 04 Lun: 00
> > >>>   Vendor: ATA      Model: INTEL SSDSA2M080 Rev: 02M3
> > >>>   Type:   Direct-Access                    ANSI  SCSI revision: 05
> > >>> "
> > >>>
> > >>> Sometimes I am see the following messages that indicate discard is
> > >>> disabled during runtime:  
> > >>>
> > >>> Relevant dmesg:
> > >>>
> > >>> ...
> > >>> EXT4-fs (sdw): mounted filesystem with ordered data mode. Opts: nobarrier,discard
> > >>> EXT4...... 
> > >>>
> > >>> .... (some time later) 
> > >>>
> > >>> EXT4-fs warning (device sdw): release_blocks_on_commit:2672: discard not supported, disabling
> > >>> EXT4-fs warning (device sds): release_blocks_on_commit:2672: discard not supported, disabling
> > >>> EXT4-fs warning (device sdt): release_blocks_on_commit:2672: discard not supported, disabling
> > >>> EXT4-fs warning (device sdu): release_blocks_on_commit:2672: discard not supported, disabling
> > >>> EXT4-fs warning (device sdv): release_blocks_on_commit:2672: discard not supported, disabling
> > >> Please check whether your ssd works with discard or whether your ssd
> > >> firmware has the ability to do so.
> > >> I used an SSDSA2M160(I guess you are using the same type as me except
> > >> the volume size is 80g, but you have to find it out from intel side) and
> > >> after I upgraded my firmware to the new version(you can download it from
> > >> intel site), it supports discard now.
> > > 
> > > 
> > > Firmware is up to date as of a few weeks ago.  It is 02M3 which still
> > > looks to be the current version. 
> > ok...
> > So please check whether your device supports discard or not.
> > Intel has a tool named Intel SSD Toolbox, and it can check the status of
> > your ssd, but the bad thing is that it seems to only have a windows
> > version...
> 
> Actually you can query that with hdparm -I /path/to/the/device and you
> should see something like
> 
> *   Data Set Management TRIM supported
> 
> in the output.

I see 

*	Data Set Management TRIM supported
...
*	Deterministic read after TRIM

set on my devices. 

Thanks,
  Keith 


> Thanks!
> -Lukas
> 
> > 
> > Regards,
> > Tao
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