From: Tim Walberg <twalberg@comcast.net>
To: linux-btrfs@vger.kernel.org
Subject: Re: question re: trim in btrfs
Date: Tue, 18 Oct 2016 14:06:59 -0500 [thread overview]
Message-ID: <20161018190659.GC5559@comcast.net> (raw)
In-Reply-To: <20161018174238.GB5559@comcast.net>
Forgot to mention - this was on a rather crusty 4.2.6 kernel. Just upgraded to 4.8.1
and the issue appears to have been resolved...
On 10/18/2016 12:42 -0500, Walberg, Tim wrote:
>> Unless I'm misinterpreting something it appears that maybe btrfs doesn't pass
>> fstrim commands down to the underlying drives when being used in a RAID-1 config.
>>
>> I have this output from a small script I wrote to run at boot time (and also via
>> cron.weekly), rather than using continous trim in the boot options:
>>
>> # cat /var/log/trim.log
>> Thu Oct 13 07:40:07 CDT 2016
>> /boot: 454 MiB (476062720 bytes) trimmed
>>
>> Thu Oct 13 07:40:08 CDT 2016
>> /: 8.9 GiB (9585152000 bytes) trimmed
>>
>> Thu Oct 13 07:40:22 CDT 2016
>> /btrfs/0: 0 B (0 bytes) trimmed
>>
>> /boot and / are mdraid RAID 1 on partitions 1 and 3 of two Samsung 850 Pro SSDs.
>> /btrfs/0 is a btrfs-raid RAID 1 of partition 4 on the same two drives. The btrfs
>> case does not seem to accomplish anything. By comparison, I have the same drive
>> in my laptop, but just a single one, and the non-btrfs-raid-1 file system on one
>> of its partitions does run fstrim successfully.
>>
>> This is quite possibly a known limitation, but I didn't find anything about it
>> through some quick searching. Maybe I didn't dive deep enough...
>>
>> --
>> twalberg@gmail.com, twalberg@comcast.net
>> --
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End of included message
--
twalberg@gmail.com, twalberg@comcast.net
next prev parent reply other threads:[~2016-10-18 19:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-18 17:42 question re: trim in btrfs Tim Walberg
2016-10-18 19:06 ` Tim Walberg [this message]
2016-10-18 21:31 ` Jeff Mahoney
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