Hi everyone.
I was trying to verify that discard (TRIM) was disabled on my system
(new fresh install on a SSD) when I found some weird things.
Indeed it seems I have many sectors to zero; example:
root@o9020:~# hdparm --read-sector 54003000 /dev/sda
/dev/sda:
reading sector 54003000: succeeded
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000
...
0000 0000 0000 0000 0000 0000 0000 0000
According to me, only my /boot partition should have zero (as this is
the only one unencrypted):
root@o9020:~# parted /dev/sda "unit s print"
Model: ATA LITEONIT LCS-128 (scsi)
Disk /dev/sda: 250069680s
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 2048s 1953791s 1951744s primary ext4 boot
2 1955838s 250068991s 248113154s extended
5 1955840s 250068991s 248113152s logical
root@o9020:~# lsblk /dev/sda -f
NAME FSTYPE LABEL MOUNTPOINT
sda
├─sda1 ext4 /boot
├─sda2
└─sda5 crypto_LUKS
└─sda5_crypt (dm-0) LVM2_member
├─VolumeGroup1-root (dm-1) ext4 /
├─VolumeGroup1-swap (dm-2) swap [SWAP]
├─VolumeGroup1-usr (dm-3) ext4 /usr
├─VolumeGroup1-tmp (dm-4) ext4 /tmp
├─VolumeGroup1-opt (dm-5) ext4 /opt
├─VolumeGroup1-var (dm-6) ext4 /var
├─VolumeGroup1-home (dm-7) ext4 /home
└─VolumeGroup1-backups (dm-8) ext4 /backups
root@o9020:~# dmsetup table
VolumeGroup1-home: 0 97648640 linear 254:0 83978240
VolumeGroup1-usr: 0 19529728 linear 254:0 25389056
VolumeGroup1-var: 0 19529728 linear 254:0 64448512
VolumeGroup1-swap: 0 15622144 linear 254:0 9766912
VolumeGroup1-root: 0 9764864 linear 254:0 2048
VolumeGroup1-backups: 0 39059456 linear 254:0 181626880
sda5_crypt: 0 248109056 crypt aes-xts-plain64
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
0 8:5 4096
VolumeGroup1-opt: 0 9764864 linear 254:0 54683648
VolumeGroup1-tmp: 0 9764864 linear 254:0 44918784
Is it expected?
Does I have to fully fill the encrypted partition (at least once) to
hide my datas?
FYI I verified TRIM and it seems really disabled:
root@o9020:/tmp# fstrim -v /tmp/
fstrim: /tmp/: FITRIM ioctl failed: Operation not supported
Thanks a lot for your help.
NB: I'm using Debian (Wheezy/Stable):
root@o9020:~# dpkg -l cryptsetup lvm2 dmsetup|tail -3
ii cryptsetup 2:1.4.3-4
amd64 disk encryption support - startup scripts
ii dmsetup 2:1.02.74-8
amd64 Linux Kernel Device Mapper userspace library
ii lvm2 2.02.95-8
amd64 Linux Logical Volume Manager
_______________________________________________
dm-crypt mailing list
dm-crypt@xxxxxxxx
http://www.saout.de/mailman/listinfo/dm-crypt
