Monthly Archives: June 2013

get drive serial numbers from NetApp DS4243 shelves strapped to Linux server

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When doing data recovery on a failed 3Ware RAID group, I utilized a couple spare NetApp DS4243 shelves. I put all the SATA drives into brackets, popped a quad port SAS card into a 1U server, and booted my rescue image from the network. The Debian OS was able to see each individual drive, at which point I could make ddrescue copies, and edit the 3Ware DCB metadata using hexedit. Keeping everything straight was quite a challenge. This one liner helped me find all the serials, and get the copies sorted out:

# for i in `ls /dev | grep sd | sed -e 's/[0-9]//' | sort -u`; do echo -n "/dev/$i " ; smartctl --all /dev/$i | grep "Serial number" | awk '{print " --- " $3}'; done;
/dev/sdaa  --- 9VS0R3T4
/dev/sdab  --- 9VS3SSJE
/dev/sdac  --- 9VS2K1DY
/dev/sdad  --- 9VS07FMW
/dev/sdae  --- 9VS402AA
/dev/sdaf  --- 9VS3V74N
/dev/sdag  --- 9VS388JX
/dev/sdah  --- 9VS2AQ9A
/dev/sdai  --- 9VS3THY9
/dev/sdaj  --- 9VS4EE3T
/dev/sdak  --- 9VS0FXWA
/dev/sdal  --- 9VS34DAD
/dev/sdam  --- 9VS45C9J
/dev/sdan  --- 9VS4L45S
/dev/sdao  --- 9VS2K9K1
/dev/sdap  --- 9VS2D631
/dev/sdaq  --- 9VS2L1BK
/dev/sdar  --- 9VS4DYDB
/dev/sdas  --- 9VS3T33R
/dev/sdat  --- 9VS3YE1K
/dev/sdc  --- 9VS1HWAM
/dev/sdd  --- 9VS1J9F3
/dev/sde  --- 9VS1L0FY
/dev/sdf  --- 9VS1H3RB
/dev/sdg  --- 9VS1JNPW
/dev/sdh  --- 9VS1GWGK
/dev/sdi  --- 9VS1DLZZ
/dev/sdj  --- 9VS1FSRD
/dev/sdk  --- 9VS3A8GZ
/dev/sdl  --- 9VS1L8ZZ
/dev/sdm  --- 9VS1JE7E
/dev/sdn  --- 9VS1CHE1
/dev/sdo  --- 9VS295R5
/dev/sdp  --- 9VS1HR8P
/dev/sdq  --- 9VS1EJQW
/dev/sdr  --- 9VS1A4V5
/dev/sds  --- 9VS1JGP8
/dev/sdt  --- 9VS1HPGB
/dev/sdu  --- 9VS1JAWZ
/dev/sdv  --- 9VS1JG8K
/dev/sdw  --- 9VS1JA51
/dev/sdx  --- WD-WMATV4441330
/dev/sdy  --- 9VS38GT3
/dev/sdz  --- 9VS4SQJX
#

append file with wget

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To append a file with one fetched from a URL, use wget and output to STDOUT then redirect and append where needed.

# wget -q 'http://10.11.178.141/all_pub_keys' -O - >>/root/.ssh/authorized_keys

In this case I wanted to add some public keys to an existing authorized_keys file.

show progress for dd

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By default dd is silent. It just copies whatever blocks you want from in to out. In order to see progress, send it a USR1 signal using kill.

Start a useless dd:

# dd if=/dev/zero of=/dev/null

In another terminal find the pid:

# ps aux | grep dd | grep -v grep
root      7784 90.5  0.0   2884   560 pts/9    R+   10:01   0:06 dd if /dev/zero of /dev/null
#
# kill -USR1 7784

The original window will now show this:

# dd if=/dev/zero of=/dev/null
14501614+0 records in
14501614+0 records out
7424826368 bytes (7.4 GB) copied, 16.2149 seconds, 458 MB/s

Then you can ctrl+c it to get the final output:

# dd if=/dev/zero of=/dev/null
14501614+0 records in
14501614+0 records out
7424826368 bytes (7.4 GB) copied, 16.2149 seconds, 458 MB/s
16888077+0 records in
16888076+0 records out
8646694912 bytes (8.6 GB) copied, 19.3507 seconds, 447 MB/s

This one liner will start your dd, then monitor it and output progress every 20 seconds. Once the dd is finished it will stop and give your shell back.

dd if=/dev/zero of=/dev/null & pid=$! && sleep 20s && while true; do i=`ps aux | awk '{print $2}' | grep ^$pid$`; if [ "${i:-a}" !=  "$pid" ]; then break; fi; kill -USR1 $pid; sleep 20s; done;