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Current main topics of interest are: science, computer technology, RAID, hardware power consumption and FreeBSD.

Last days i've been working on completing the geom raid5 expansion script, that allows to add one or more disks to an existing RAID5-array controlled by geom_raid5. The script is more-or-less finished, but now requires extensive testing. Any bug in the script or the procedure may destroy data, so testing is very important here.

If you have a system with multiple harddrives lying around, for example if you have not yet taken the machine into production usage, you can help me test my script. If you have the time and patience, this is the procedure:

Caution: this should not be attempted on a system containing real files, the expansion procedure is BETA and is provided to you as means of testing it, not actually performing the procedure on real files without a proper backup!


Step 1)
Install FreeBSD 6.2 ot 6.3 in either i386 (32-bit) or amd64 (64-bit) mode. Be sure to install the sourcecode under /usr/src (option "src" in the installer).
note: you need a working internet connection (dhclient <interface> will use DHCP)

Step 2)
Install geom_raid5 per installscript:
fetch http://www.fluffles.net/files/installgraid5
chmod 700 installgraid5
./installgraid5

Step 3)
Install PHP in CLI-mode and calc:
cd /usr/ports/lang/php5
make config (enable the CLI-option and uncheck everything else if you don't use PHP for anything else)
make install clean

Step 4)
Install calc external calculator:
pkg_add -r calc
(or via ports in /usr/ports/math/calc)

Step 5)
Create a RAID5 array, leaving one or two disks free to be used for expansion
graid5 label data ad1 ad2 ad3

Step 6)
Populate the RAID5 array with real files and fill it up:
newfs /dev/raid5/data
mount /dev/raid5/data /mnt
cp -R /usr/* /mnt/
(or use another source than /usr/ to copy files from, at least make sure the RAID5 filesystem is quite full)

Step 7)
Check the filesystem for errors:
umount /mnt
fsck -t ufs /dev/raid5/data

Step 8)
Start the expansion process:
fetch http://www.fluffles.net/files/graid5-expand
chmod 700 graid5-expand
./graid5-expand data ad4
(note: "data" is the array name as found in "graid5 status" and "ad4" is the disk you wish to add to the RAID5 array. You can specify multiple disks seperated with spaces to add two or more disks at once. Please test this too if possible.

Step 9)
Expand the UFS filesystem:
growfs /dev/raid5/data2
note: your expanded array now has a new name, data2 in this example.

Step 10)
After growfs, check the filesystem for errors:
fsck -t ufs /dev/raid5/data2
mount /dev/raid5/data2 /mnt
df -h
note: make sure the Used space equals how you left the filesystem before expansion.


Key points:
Does the internal and external calculator work fine on i386/amd64 mode?
Is the growfs-bug fixed now that we zero-write the expanded LBA-space?
You should not see any errors reported by fsck

Please report your findings to me via email, info )at( fluffles.net
This would help me and others a lot! Thank you!