Jimmy's weblog

Growing Hardware RAID-5 with arcconf

jimmy — Tue, 15 May 2012 18:26:06 +0000

Maybe you read my previous post “Growing Hardware RAID-5 with LVM by adding a physical disk” where I described how to add another disk to a RAID-5 with the MegaCLI tool. For older ServeRAID controllers you have to use the arcconf tool instead, e.g. ServeRAID-8k, which was shipped in the first x3650 models. There’s plenty of documentation about arcconf but how to resize a raid was hard to find. The MODIFY command is used for resizing and let’s assume that we have 3 disks in the array and add another one (same as in my previous post)

./arcconf modify 1 from 1 to MAX 5 0 0 0 1 0 2 0 3

The syntax of arrconf is:

./arcconf MODIFY  FROM  TO [Options]    [CHANNEL# DRIVE#] [noprompt]

So in our case it was Controller# 1 and LogicalDrive# 1 and MAX means to use all capacity that will be available. Raidlevel will still be level 5 and the harddisks are [0 0], [0 1], [0 2] and the new [0 3].
To watch the status of the raid migration, use

./arcconf getstatus 1

JFYI: To add another 146 GB SAS (15k) to the raid it took about 12 hours to rebuild the array.

Growing Hardware RAID-5 with LVM by adding a physical disk

jimmy — Thu, 22 Dec 2011 23:00:58 +0000

Sometimes you’re running out of space and all you can do is adding additional disks. Although it’s a simple task in theory, there a some risky steps involved. So you should backup your volumes before. In my case I had a RAID-5 in an IBM x3650 M3 Server with a ServeRAID M5015 Controller. There was one volume with three 146 GB SAS disks and on top LVM. The root filesystem was on this volume, too, which doesn’t make things easier
First Step: Insert a new 146 GB SAS disk to extend the volume. The first risky step is to rebuild the RAID-5 with four disks instead of three. So you may want to upgrade the firmware of the controller first and make a backup of the LVM volumes. Of course you should not save the backup on the same server
I configured a partimage server on another machine and ran partimage client on the server with the new disk:

partimage -z2 -domMc -s 192.168.0.7 save /dev/mapper/main-rootfs fileserver.partimg.bz2

(Please lookup the options in the manpage yourself)
The command for the ServeRaid controller was not easy to find but here we go:

/opt/MegaRAID/MegaCli/MegaCli64 -LDRecon -Start -r5 -add -PhysDrv [252:3]  -L0 -a0

252:3 stands for the fourth drive. You can find out more about available drives running:

/opt/MegaRAID/MegaCli/MegaCli64 -PDList -a0

To watch the rebuild status run:

/opt/MegaRAID/MegaCli/MegaCli64 -LDInfo -L0 -a0

As we want to resize the root filesystem we need to reboot the machine so that programs like fdisk see the new size of the array. Afterwards you can resize the partition or simply delete and recreate it. Next step is to resize the LVM physical volume and again a reboot is needed so that pvresize recognizes the new partition size. So these are the next steps where things might get wrong, too:

pvresize -v /dev/sda2
lvresize -l +34871 /dev/main/rootfs
resize2fs /dev/main/rootfs

/dev/sda2 was my LVM partition (sda1 was for /boot) and thanks to the new disk I had 34871 extends available (146 GB). The resize commands work with active volumes and mounted filesystem so you don’t have to stop any services. Only the two or three reboots (if you want to make a final reboot after all changes) interrupt the services but this should be ok.

Upgrading Samba from plaintext passwords to encrypted passwords

jimmy — Thu, 10 Nov 2011 15:23:31 +0000

Recently I had to upgrade a samba installation which was using plaintext passwords. This is not as rare as one might think because some companies couldn’t upgrade from win95 PCs as those were coupled to machines which didn’t support newer versions. For plaintext passwords samba uses /etc/passwd and /etc/shadow to find out usernames and passwords. With encrypted passwords samba uses its own database with the tdbsam backend. There was also a smbpasswd backend which is now deprecated. But it’s very handy if you want to upgrade to encrypted passwords without having every user to enter her password again to fill the new database. There is the global option “update encrypted = yes” which replaces a plaintext password with an encrypted one when the user logs in. The plaintext password is written to the smbpasswd file defined in smb.conf (This does not work with the tdbsam backend but you can migrate from smbpasswd to tdbsam easily afterwards). So before we let the users login again we have to generate a smbpasswd file. One way to achive this is to run this command:

cat /etc/passwd | mksmbpasswd >> /etc/samba/smbpasswd

(assuming that “passdb backend = smbpasswd:/etc/samba/smbpasswd” is in your smb.conf)
After all users have logged in (check smbpasswd file for filled in passwords) you can disable plaintext auth.

Watch out for bug in WinXP SP3 with plaintext auth!
When I made this migration it happened that this procedure was working great for some clients where others completely failed to login. I found out that Win7 clients and WinXP clients with SP2 worked, but WinXP clients with SP3 were failing. The reason is simply a bug caused by patch KB2536276. You can find the full story in bugzilla of samba: Windows security patch KB2536276 prevents access to shares
In my case I was lost and had to ask the users to type in their passwords again but there seems to be a workaround if you read the last comments in the bugreport (changing domain name)

Grazer Linuxtage 2011

jimmy — Tue, 15 Mar 2011 15:28:18 +0000

Hope to see you there

Using IBM Bootable Media Creator on Debian

jimmy — Thu, 05 Aug 2010 23:03:25 +0000

IBM provides a tool called “Bootable Media Creator” (bomc) which creates bootable media - like an usb key - that allows you to easily install all firmware updates even if there is no OS installed on the server. You just select your server model, e.g. x3650, and the tool downloads all available updates. This saves a lot of time.
Formerly I used bomc on a SLES server but now I wanted to try if it would work on my Debian notebook, since the tool is available as a single binary and not as a rpm package as usual.
It started up and seemed to work but unfortunately after downloading some packages it stopped with an error. Long story short: I just copied the SuSE-release file to my /etc on my Debian notebook and all errors were gone
My /etc/SuSE-release looks like this:

SUSE Linux Enterprise Desktop 10 (i586)
VERSION = 10

Bomc can be downloaded at the IBM site

Dirty dirvish hack to use “localhost” as client option

jimmy — Sun, 16 May 2010 09:03:46 +0000

When using dirvish you usually have to use the local hostname for the client option in default.conf. In other words, the output of the command “hostname”. If it’s different than the client option than dirvish assumes that it’s a remote transfer and uses ssh to connect. So you can not use “localhost” which would be rather straightforward ;-(
Lately I needed dirvish on a sytem with heartbeat where two systems share one configuration but have different hostnames. Because I was so angry about this IMO stupid check with “hostname” I made a dirty hack…
Line 258 in /usr/sbin/dirvish looks like this:

chomp($$Options{Server} = `hostname`);

I changed it to:

chomp($$Options{Server} = localhost);

This way dirvish assumes localhost as local tranfer and everything else as remote. The check itself can be found in line 520.
Remember, this hack is really evil. There are several better ways to solve the problem.

Linuxtage 2010

jimmy — Fri, 23 Apr 2010 06:18:55 +0000

Only one day left. I’ll be there at the grml-booth, which is a must see, again. See you there

Linuxtage Graz 2009

jimmy — Thu, 23 Apr 2009 06:05:47 +0000

See you there

OpenOffice and Freefonts

jimmy — Tue, 01 Apr 2008 12:55:40 +0000

Today I tried an upgrade of my debian unstable machine. Didn’t do this for several months, so I expected some problems, but this one was really hard to solve. I already had openoffice 2.4 installed, so there weren’t many changes, but after the complete upgrade the free fonts disappeared (FreeSans, FreeMono, …). The font drop-down menu showed three blank lines and I was also able to type in the word “FreeSans” into the box, but all I got were blank spaces. I googled around for two hours and finally I found a hint about the ttf-freefont package: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=472830. I don’t understand exactly what’s wrong, but installing version 20060501cvs-12 from snapshot.debian.net solved the problem and the fonts get now rendered correctly.

IBM Server x3350

jimmy — Wed, 30 Jan 2008 19:35:00 +0000

A few months ago I bought the new x3350 Server. Previously the x3250 was my standard model for small solutions. But I was always missing some important features which are now available with the x3350. These are:

Hot-swap redundant power supplies
Dual Gigabit Ethernet for bonding
Light path diagnostics

Thank you IBM for exactly implementing my wishlist

When I installed Debian etch on the machine everything worked fine except the broadcom NICs. They were not detected so I had to use a newer kernel.
The problem was solved when “Etch and a half” was released because the 2.6.24 kernel includes a newer tg3 module.