[mythtv-users] SSD disk for the frontend

[Igor Cicimov]

On 26/04/2013 9:49 AM, "Josu Lazkano" <josu.lazkano at gmail.com> wrote:
>
> Hello, thanks for the reply.
>
> 2013/4/25 Igor Cicimov <icicimov at gmail.com>:
> >
> > To optimize the SSD performance you need to enable TRIM for your SSD.
You
> > can check for it like this:
> >
> > # hdparm -I /dev/sdb | grep -i trim
> >   * Data Set Management TRIM supported (limit 8 blocks)
> >   * Deterministic read data after TRIM
>
> This is the output of the command:
>
> # hdparm -I /dev/sda | grep -i trim
>   * Data Set Management TRIM supported (limit unknown)
>
> Is this OK?
>
Yes

> >
> > Then you need to add the 'discard' option to the partitions on the SSD
drive
> > in /etc/fstab. On my system:
> >
> > # / was on /dev/sdb2 during installation
> > UUID=7a71b85c-42e6-4135-b117-b4505cdbfd6e /               ext4
> > errors=remount-ro,discard 0       1
> > # /home was on /dev/sdb4 during installation
> > UUID=0a7b2dec-a8e4-4634-bc3b-3f67bcb41443 /home           ext4
> > defaults,discard        0       2
> >
> > but you need ext4 for this. You can also add 'noatime' too to the
options to
> > reduce the SSD writes and increase its lifetime. Then reboot the system.
>
> This is my original fstab file:
>
> # cat /etc/fstab
> UUID=3d4a3495-832b-40eb-881a-ac77497feb30 /               ext4
> errors=remount-ro 0       1
> UUID=fda3b8ef-5fa0-49ee-a5ef-1a12e78f1db8 none            swap    sw
>            0       0
>
> I change it to this:
>
> # cat /etc/fstab
> UUID=3d4a3495-832b-40eb-881a-ac77497feb30 /               ext4
> errors=remount-ro,discard,noatime 0       1
> UUID=fda3b8ef-5fa0-49ee-a5ef-1a12e78f1db8 none            swap    sw
>            0       0
>
> Is this correct?
>
Yes but you need remount/reboot for that to take effect.

> > To see the trimming in action you can run:
> >
> > # fstrim -v /
> > # fstrim -v /home
>
> I don't understand fstrim commands, this my output:
>
> # fstrim -v /
> /: 48443392 bytes were trimmed
>
> What that is means? Is this correct?
>
Means trimming is working.

> > You can also set the above as a daily cronjob if you want to execute
> > trimming on runtime apart from boot time.
> >
> >
> > In case you have a bad inodes or any kind of filesystem corruption I
would
> > recommend to reset the SSD to factory settings. The SSD after booting is
> > protected by the BIOS so you need to boot with the SSD disconnected
(from
> > live cd probably), then connect it and execute the following procedure
> > (replace sdb with what ever it shows up on your system, run blkid to
find
> > it):
> >
> > # dcfldd if=/dev/zero of=/dev/sdb bs=4k
> > # hdparm --user-master u --security-set-pass Eins /dev/sdb
> > # hdparm --user-master u --security-erase Eins /dev/sdb
> >
> > and then set your fstab as above (and don't forget to replace sdb and
UUID
> > as appropriate for your case) and reboot.
>
> If a do this steps, will I erase all data of the disk?
>
Yes

> Is this necessary?
>
Only if you think you have corrupt file system.

> > Hope this helps.
> >
> > Igor
>
> Thank you very much for your great reply.
>
> Best regards.
>
> --
> Josu Lazkano
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