Fireproof backup: another update

A little bit more than one year after replacing it, my backup disk was starting to show signs of weakness, so it was time for another replacement. This time, I was able to find a 1.5 Tb disk that does not require an external power supply. With this disk size I will be able to keep 2 weeks of backup and fully automatize the removal of old backups (it’s currently a manual process).

But this disk is so new that it is not really well supported by Linux. The first step was to update the /usr/share/smartmontools/drivedb.h file with the following entry, so smartmontools can recognize it:

{ "USB: Seagate FreeAgent Go Flex USB 3.0; ",
"0x0bc2:0x5031",
"",
"",
"-d sat"
},

Unfortunately hdparm does not seem to recognize it either, but it found a way to test the standby status by using smartclt instead (I need this to be sure that the disk is really in standby mode before opening the safe – see my previous posts on this subject for the reason):

$ sudo smartctl -n standby /dev/sde
smartctl 5.41 2011-03-16 r3296 [x86_64-unknown-linux-gnu-2.6.38-2-amd64] (local build)
Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net

Device is in STANDBY mode, exit(2)

It seems that this disk is a little bit slower than the previous one – a full backup takes ~9 hours now, where with the previous disk it took a little bit more than 7 hours. The new disk is supporting USB 3.0, it’s a shame I cannot use it.

Last minor issue, there is a bug in the kernel, so each time the disk is used a spurious log entry appears in syslog:

[171412.410641] sd 16:0:0:0: [sde] Sense Key : Recovered Error [current] [descriptor]
[171412.418494] Descriptor sense data with sense descriptors (in hex):
[171412.425309] 72 01 04 1d 00 00 00 0e 09 0c 00 00 00 00 00 00
[171412.432089] 00 00 00 00 40 50
[171412.436059] sd 16:0:0:0: [sde] ASC=0x4 ASCQ=0x1d

It seems that there is a patch available for this problem, but I do not see it applied in the latest kernel yet.

Update 05/22/2011:

A full backup with USB 3.0 takes only 13% less time than with USB 2.0. So more or less the same speed that I had before changing the disk. It also seems that the USB 3.0 driver is not complete as I had to force -d sat,12 to use smartctl, and the disk never goes to standby mode. And as expected, Linux 2.6.39 does not fix the sense data bug.

Update 11/19/2011:

Problem finally fixed in Linux 3.1.

Update 07/15/2013:

Fixed link to previous post on this subject.