[zfs-discuss] ZFS and TRIMming procedures

Gordan Bobic gordan.bobic at gmail.com
Tue Apr 12 12:04:30 EDT 2016


Indeed, or use host-protected space functionality of the disk (standard
SATA feature) to make it appear smaller than it actually is.
As long as the the firmware has enough untainted blocks (be it from empty
space or overprovisioning), it will not slow down.


On Tue, Apr 12, 2016 at 5:01 PM, Mihai Vintila via zfs-discuss <
zfs-discuss at list.zfsonlinux.org> wrote:

> There is a simple solution for overcoming trim but you need to know your
> ssd well.
> For example:
> intel s3600 allows up to 95% space utilization before performance drop
> samsung 840/850 up to ~ 70%
> crucial  m5xx  ~ 90%
>
> So to overcome the missing trim simply avoid filling the disc which you
> can best do by creating partitions from beginning or just watch the space
> utilization for individual ssd.
>
> Best regards,
> Vintila Mihai Alexandru
>
> On 4/12/2016 4:17 PM, Kash Pande via zfs-discuss wrote:
>
> This isn't true, not in all cases anyway. For systems with L2ARC, the
> performance can slow to a crawl without occasionally removing the SSD,
> running TRIM, and reinserting it. The performance will remain crap until
> the L2ARC is full, and then eventually it slows again.
>
> The new Nexenta TRIM support will help with this, when the l2arc devices
> use TRIM.
>
> Kash
>
> On 12/04/16 04:29 AM, Gordan Bobic via zfs-discuss wrote:
>
> Why do you think you even need to TRIM your SSDs? SSDs these days are
> adequately over-provisioned and have good enough wear levelling that you
> shouldn't need to do it. I certainly never did it to any of my SSDs (Intel,
> Kingston, Crucial) and they all still run and perform just fine years on.
>
> On Tue, Apr 12, 2016 at 4:28 AM, fddi via zfs-discuss <
> <zfs-discuss at list.zfsonlinux.org>zfs-discuss at list.zfsonlinux.org> wrote:
>
>> Hello,
>> I plan to use ZFS on serveral servers which have a 8 disk raidz2 or
>> eventually 4 disk raidz + ZIL And L2ARC disk.
>> Anway I am concerned about TRIM of SSD disk.
>> What procedure should I use for trimming the SSD disks ?
>> Can I simply take a disk out of the raidz, TRIM it and put it back
>> (Resilvering) ?
>> Smees that  ZFSonLinux lacks of TRIM support for SSD disks ?
>> if so which is the bes proceduret to trim a SSD disk ? unfortunately
>> there is no tune2fs possibility for trimming as  on ext4 or xfs
>> or mount with discard option.
>>
>> thank you
>>
>> Rick
>>
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>
>
>
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