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From: Christian Balzer <chibi@gol.com>
To: linux-raid@vger.kernel.org
Subject: RAID5 TRIM/DISCARD user land support (fstriim and mkfs)
Date: Mon, 10 Aug 2015 16:46:57 +0900	[thread overview]
Message-ID: <20150810164657.75bae079@batzmaru.gol.ad.jp> (raw)


Hello,

Debian system, tested both Wheezy and Jessie, thus 3.16 kernel with
backports.

8 SSD RAID5, of course with raid456.devices_handle_discard_safely set to 1.
I can re-mount it with discard w/o a problem:
---
EXT4-fs (md4): re-mounted. Opts: stripe=112,data=ordered,discard
---

However fstrim whines about "FITRIM ioctl failed: Operation not supported"
and mkfs.ext4 unsurprisingly doesn't discard things when invoked.

The same HW/OS combo works fine with RAID10.

When looking at the sysfs entries for that MD device the fact
that /sys/class/block/md4/queue/discard_zeroes_data is 0 doesn't instill
me with hope or confidence 

Now while the SSDs in question (Intel DC S3610s) don't really need TRIM
really would have liked them to be able to start with a clean slate so to
speak.

Any insights?

Christian
-- 
Christian Balzer        Network/Systems Engineer                
chibi@gol.com   	Global OnLine Japan/Fusion Communications
http://www.gol.com/

             reply	other threads:[~2015-08-10  7:46 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-10  7:46 Christian Balzer [this message]
2015-08-10  8:28 ` RAID5 TRIM/DISCARD user land support (fstriim and mkfs) Holger Kiehl
2015-08-10  8:53   ` Christian Balzer
2015-08-10  8:59     ` Holger Kiehl
2015-08-11  5:20 ` Christian Balzer

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