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reading raw disk of Dell perc RAID adapter
by James Harper 19 Jan '12

19 Jan '12

I have been handed a raw disk of a Dell perc (I think) RAID adapter. It was a RAID1 array but the machine is broken and can't be repaired in the short term. I was expecting to be able to track down the partition table at some offset into the disk and then identify the partitions etc but of course it's not that easy. I've found a few instances of the 0x55 0xaa partition signature at the end of a sector but only one actually appears to be a partition table (about 64MB from the start of the disk), but even then it doesn't look right. I then tracked down an NTFS signature (the disk is out of a Windows machine but I'm trying to get the data off on a Linux machine) but ntfs-3g and other tools says it's corrupt. So I'm guessing that one of the following is happening: 1. The RAID controller crapped all over the disk before the system failed and it is actually corrupt 2. The RAID is actually RAID0 (I was assured it was RAID1 but you know how these things go) 3. Dell have some non-linear mapping of partitions dmraid doesn't know anything about it, which kind of makes sense as the Dell raid controllers are normally not fakeraid. Any suggestions? Thanks James

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Linux and music
by Kathy Reid 13 Jan '12

13 Jan '12

Hi everyone, Happy new year! If anyone has any advice for me on the following, it would be very much appreciated. Problem statement: I'm reliant on Windows for music. I own an iPod shuffle, and am reliant on iTunes to download music to this device. What I would like to do is buy another, non-Apple music player, and fulfill the following requirements; 1. Run a music program within Linux (Ubuntu / Unity) 2. Download music legally within Linux 3. Load my music player from within the music program 4. Convert the music from iTunes/Apple format and have it available to the Linux music program. What are my options? Regards, Kathy

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Sympa MySQL changes mean upgrades are difficult
by Jesse Stevens 12 Jan '12

12 Jan '12

Heya again I've found that my previous question RE moving Sympa can be partially fixed. I've found that on the new server running the sympa --upgrade will set things ready to go but still have no subscriber data. If I then manually dump the entries from the MySQL database (subscribers_table) on the old Sympa server to the new in the right place, and then go to the column created which didn't exist on the old server (robot_subscriber) and add the proper robot details relating to the new server, the subscriber will attach as it's supposed to! I've been using phpmyadmin to browse the tables and check out the structure as I'm really not that much of a MySQL admin, so does anyone know what I could use to change the contents of every single entry for "robot_subscriber" in the table "subscriber_table" in the database "sympa" ? Also this raises another question - why is grabbing a subscriber list so difficult? To me it would be a vital thing to be able to dump this list in whatever format you'd like for easy backups and fail safe restoration. Sometimes these lists can be thousands of entries! Any help is very much appreciated Jesse

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Migrating from an ancient Sympa to modern Sympa setup
by Jesse Stevens 12 Jan '12

12 Jan '12

Hey there list - long time no speak! I've been migrating everything off an ancient Debian 3 Server (kernel 2.2.20!!) which was until just now still in use. Mostly things are going well except for trying to get Sympa off it. Basically it's running Sympa 4.1.5 using MySQL for data storage. According to what I've ready I really just need to copy the MySQL database, mail list home configs (/var/lib/sympa/*) and once copied, run the sympa --upgrade tool. Doing it this way simply upgrades the database structure and dumps all of the subscription information. The mailing lists survive but with subscibers which isn't good. I see that I can run sympa --dump to dump the subscribers into files located at /var/lib/sympa/expl/maillinglistname/subscribers.db.dump But the format of this file doesn't allow importing into sympa via sympa --import=listname ./filename The formats are different. Does anyone have any idea of what I can do here? My preferred path was to create the lists nice and fresh on the new server from scratch, and simply import subscribers but I can't find a path to do that. Is there perhaps a script that will perform the conversion around that someone else has used? I can't seem to find more info in the googling I've done.. Jesse

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Debian, multiarch and installing 32-bit libraries on x86-64
by Jason White 12 Jan '12

12 Jan '12

I'm running Debian Sid (reasonably up to date). To run a particular 32-bit executable on my x86-64 machine, it appears that I need a 32-bit x86 version of libz.so. The error message from the executable is: error while loading shared libraries: libz.so.1: wrong ELF class: ELFCLASS 64 Given what is happening with Debian multiarch, which is supposed to solve this problem, what's the correct way to install the library at the moment?

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XFS and fstrim
by Craig Sanders 07 Jan '12

07 Jan '12

Does anyone use fstrim on an XFS formatted SSD partition? I've got two systems with XFS root partitions that fstrim seems to do (almost) nothing on, but it seems to work correctly on another system with formatted with ext4. Details follow: System 1 is an AMD 1090T with a Patriot Torqx 2 128GB SSD. System 2 is also an AMD 1090T with a Patriot Pyro 120GB SSD. I've been running both for several months without any TRIM support because I (incorrectly) assumed that XFS' support for TRIM was automatically enabled. I've recently discovered that it's not, and also that it's better performance-wise to run fstrim regularly from cron for 'batch-mode' TRIM operations. Anyway, System 1 takes over 7 minutes to run fstrim, and claims to have trimmed about 16GB....but if i run it again it still takes over 7 minutes and claims to have trimmed about the same amount of data (slightly less). # time fstrim -v / /: 16777764864 bytes were trimmed real 7m31.089s user 0m0.004s sys 0m9.705s # time fstrim -v / /: 16772276224 bytes were trimmed real 7m8.973s user 0m0.000s sys 0m9.165s System 2 takes over 28 minutes to run fstrim and claims to trim about 51GB of data (it's had an SSD for a lot longer than System 1. It also has /home on /, whereas System 1 has /home on a separate disk). similarly, running it again immediately afterwards also takes about the same amount of time and claims to trim about the same amount of data. # time fstrim -v / /: 51594948608 bytes were trimmed real 28m19.832s user 0m0.000s sys 0m6.264s # time fstrim -v / /: 51499814912 bytes were trimmed real 28m29.230s user 0m0.000s sys 0m6.328s (interestingly, the Pyro is a *much* faster SSD than the Torqx2. it's SATA3 and is capable of about 500-550MB/s. The Torqx 2 is SATA 2 and is capable of about 230MB/s...seems as if TRIM speed is roughly the same for both drives, proportional to the amount of data to be trimmed. almost certainly limited by the flash speed with the internal controller differences being negligible for this task) OK, so it seems as if fstrim claims X bytes were trimmed, but it doesn't actually happen. On a third system, I have / on an SSD formatted with ext4. System 3 is an Intel Xeon E5607, and the SSD is an OCZ AGILITY3 120GB. # time fstrim -v / /: 14267424768 bytes were trimmed real 2m25.222s user 0m0.000s sys 0m0.636s # time fstrim -v / /: 0 bytes were trimmed real 0m0.001s user 0m0.000s sys 0m0.000s on ext4 fstrim seems to work as expected. The OCZ SSD is also a LOT faster than the Patriot SSDs (roughly 14GB trimmed in 2.5 minutes). anyone seen this before? is it a bug in XFS' SSD handling? or am i just misinterpreting the results? my google-fu can't find anyone with similar problems, just mailing list articles and an XFS wiki page saying that it works, and that running fstrim regularly is recommended over using the 'discard' mount time option. craig PS: i was already thinking of reformatting these SSDs with ext4 anyway. They're mostly used as boot & OS drives, with bulk storage on a ZFS volume so don't need XFS. gives me a good excuse to replace the Torqx2 with a Pyro :) (and the Torqx2 can go into my mythtv box where it'll speed up the mythtv mysql database). -- craig sanders <cas(a)taz.net.au>

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searching for $@
by Russell Coker 06 Jan '12

06 Jan '12

When hacking some Perl code I encountered $@. It seems that is just a way of dumping the last error. Unfortunately Google doesn't help me because it only does a word based search. Does anyone know of a search engine that allows searching for such things? Also what's the best web site for finding a quick summary of what something does in Perl? -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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bad adsl connection
by James Harper 05 Jan '12

05 Jan '12

Monitoring of a remote router is reporting rtt of 1000 ms (sometimes up to 3000) and packet loss of 30-60%. If the rtt was higher I'd be expecting some sort of malicious activity going on but at 1000ms I think that's unlikely, but obviously I can't connect to find out so won't be able to investigate until tomorrow morning. Are there any tricks for connecting to a troublesome connection like that? Any way to fiddle with TCP options to send 2 copies of each packet (to overcome packet loss) and increase timeouts etc? It won't do me much good tonight but could be useful in the future. All I can really think of is to reduce MSS to give me smaller packets which might be less likely to be dropped (assuming the problem is line noise and not congestion). Thanks James

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TSO ethtool and kernel panic
by Russell Coker 05 Jan '12

05 Jan '12

I have four systems running drbd (several combinations of two-node DRBD devices) which all get "Digest integrity check FAILED" errors. One of the possible causes is TSO, so obivously I want to test running without it. ethtool -K eth1 rx off tx off sg off tso off gso off I ran the above command and saw the following in my logs before the system rebooted: Jan 4 14:39:10 hetz3 kernel: [3167347.964860] e1000e 0000:02:00.0: eth1: Reset adapter Jan 4 14:39:10 hetz3 kernel: [3167347.978907] xenbr1: port 1(eth1) entering disabled state Jan 4 14:39:14 hetz3 kernel: [3167351.681827] e1000e: eth1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx Jan 4 14:39:14 hetz3 kernel: [3167351.682167] xenbr1: port 1(eth1) entering learning state Is it expected that you can change TSO settings while the system is running? -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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Put media server into low-energy state
by Colin Fee 03 Jan '12

03 Jan '12

Happy New Year All. I want to put my media server at home into a low-energy state when no one is at home e.g. now when both myself and my wife are at work, or say overnight when we are sleeping. It runs Ubuntu Server 10.04. What strategies and utilities should I use? -- Colin Fee tfeccles(a)gmail.com

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