SSD trim

This article explains what is TRIM and how to handle in Windows platform.

Below two related to Ubutu, and I am happy to see there is already weekly job for trimming.

tail -n1 /etc/cron.weekly/fstrim 
/sbin/fstrim --all || true

http://askubuntu.com/questions/443761/how-is-trim-enabled

http://askubuntu.com/questions/18903/how-to-enable-trim

However, due to my SSD capacity is small (120GB) only, I decided to have a daily cron job instead

 as shown below..

/etc/cron.daily$ cat trimssd
#!/bin/sh
LOG=/var/log/trimssd.log
echo "*** $(date -R) ***" >> $LOG
fstrim -v / >> $LOG

hmc@hmc-P55A-UD3:/etc/cron.daily$ sudo chmod 755 trimssd
hmc@hmc-P55A-UD3:/etc/cron.daily$ sudo ./trimssd
hmc@hmc-P55A-UD3:/etc/cron.daily$ cat /var/log/trimssd.log
*** Wed, 09 Sep 2015 23:11:59 +0800 ***
/: 3.3 GiB (3499556864 bytes) trimmed

migrate ubuntu 15.04 from HDD to SSD

Factors:
a.) 9 bad sectors reported by gnome-disks.
b.) Interested on new stuff - SSD
e.) Attractive price from Comex: Sandisk 120GB only S$72.

Did some research on the web.

A good article https://help.ubuntu.com/community/MovingLinuxPartition , but seems not update-to-date. Anyway it explains what is going on in details. I followed from step 1 to 4,  and part of step 5 & 6 . Since I have no confidence on editing grub.cfg and didn't see below (maybe few detail steps is not descripted clearly)

1) UBUNTU...

• Finally, once rebooted successfully on new Ubuntu partition

As I found it still use my HDD for bootup.

Thus I abandom the "Refresh the GRUB 2 menu "

sudo update-grub

Instead , I followed below step to install grub mentioned in http://frugaltech.happystoic.com/ssdlinux and https://frankfzw.wordpress.com/2014/12/23/migrate-ubuntu-14-04-from-hdd-to-ssd/


$ sudo mount -o bind /dev   /mnt/ssd/dev
$ sudo mount -o bind /sys   /mnt/ssd/sys
$ sudo mount -t proc /proc  /mnt/ssd/proc
#$ sudo cp /proc/mounts /media/SSD/etc/mtab    --> I skip this command, as it doesn't seem to use UUID. 

$ sudo chroot /mnt/ssd
$ grub-install /dev/sdc
$ grub-install --recheck /dev/sdc       # only in case of errors in the step before
$ update-grub2

Reboot PC and Yes!18 seconds instead of previous 45 seconds.




Later on I study somemore on mtab and fstab.

Here is one short comparison : http://www.linuxquestions.org/questions/linux-newbie-8/difference-between-mtab-and-fstab-924190/

and more can be found http://ubuntuforums.org/showthread.php?t=1737715



For UUID to be used in fstab, in fact I prefer to use device ID & partition ID, as I have 2 HDDs (1TB Hitachi and 2TB Toshiba) and 1 SDD (120GB Sandisk).  Here is my fstab, easier for me to understand.

root@hmc-P55A-UD3:/etc# cat   fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
#              
# / was on /dev/sda10 during installation
# /mnt/shared was on /dev/sda8 during installation
# /mnt/staging was on /dev/sda9 during installation
# /mnt/vm was on /dev/sda7 during installation
# swap was on /dev/sda5 during installation

/dev/disk/by-id/ata-Hitachi_HDT721010SLA360_STF610MR15HK9P-part7 /mnt/vm ext3 defaults 0 2
/dev/disk/by-id/ata-Hitachi_HDT721010SLA360_STF610MR15HK9P-part8 /mnt/shared ext3 defaults 0 2
/dev/disk/by-id/ata-Hitachi_HDT721010SLA360_STF610MR15HK9P-part9 /mnt/staging ext3 defaults 0 2
#/dev/disk/by-id/ata-Hitachi_HDT721010SLA360_STF610MR15HK9P-part10 / ext4 errors=remount-ro 0 1
/dev/disk/by-id/ata-SanDisk_SDSSDA120G_152480401043-part1 / ext4 noatime,nodiratime,errors=remount-ro 0 1
/dev/disk/by-id/ata-Hitachi_HDT721010SLA360_STF610MR15HK9P-part5 none swap sw 0 0
#/dev/disk/by-id/ata-Hitachi_HDT721010SLA360_STF610MR15HK9P-part2 none swap sw 0 0
/dev/disk/by-id/ata-TOSHIBA_DT01ACA200_43J1EREGS-part1 /mnt/localubt ext4 defaults 0 2
/dev/disk/by-id/ata-TOSHIBA_DT01ACA200_43J1EREGS-part2 /mnt/shared2 ext4 defaults 0 2
 

gnome-disks a handy tool to manipulative this.



I also referenced https://radu.cotescu.com/migrating-your-ubuntu-machine-to-a-ssd-drive/

Prepared a few rescue Swiss knives like boot-repair, gparted, unetbootin, clonezilla, Ubuntu live CD (same version as my HDD) in bootable thumdrives.