Hi Roelof and others:
I uninstalled the SiI software raid card and installed SL 5.1 again! SL
5.1 seemed to be able to set up a RAID pair by itself even without the
add-on raid card! Everything was very smooth.
My config is:
2 x 160GB SATA harddisks installed on 2 separate SATA channels.
My idea is to keep one hardisk as working system disk 24 hours (science
calculation, business, BT, everything etc and therefore it will be worn
out to death easily ;) and the other harddisk as Spare disk. It will
be rebuilt and cloned per week against the working system disk. Another
file backup software will take care the incremental backup everyday!
Sound very perfect! ;)
Ok! After the above mentioned SL 5.1 system was built and became stable,
I shut down the computer. Then, I turned on the computer and
deactivated the 2nd SATA harddisk (named sdb) from within BIOS. SL 5.1
booted with the single hardisk(sda) successfully (It claimed Degraded
RAID mirror when SL 5.1 started up). I ran the system for a few days.
Then, I activated sdb again and hoped that SL 5.1 could rebuild it and
cloned sda to it. However, SL 5.1 claimed that it could not find many
files and stopped at the command prompt. I rebooted the computer,
deactivated sdb again in the BIOS and booted to SL 5.1 successfully with
only sda again!
So, I face a problem: How to REBUILD / CLONE sda to sdb with Linux
command mdadm?? :((
Timmy
P.S. After I had unplugged the SiI software SATA RAID card, SL 5.1
never stops at RedHat Nash 5.19.6 ..... any more. I guess this model of
card is not compatible with the current SL 5.1! Avoid it! :((
I never understood why redhat included the alpha quality dm-raid
drivers. I call this alpha, since basic functionality like rebuilding
a raidset (!) still is missing. DM-raid is a kludge to be able to do
dual-boot with a windows system using these raid drivers.
Never, ever use dm-raid on a server. Use mdadm instead. It performs
just as well (dm-raid is also softwaid after all) and it is stable.
If you only need mirroring, you can also use LVM to create a mirror.
(I never used that myself, YMMV)
Another advantage of mdadm is that it is hardware independent. Your
raidsets will keep on working even when transferred to a different
brand of sata controller.
By the way: if you try to install an mdadm based raid system on a
drive that previously has been part of an intel/promise/highpoint raid
set, it will probably fail after the first reboot. This is because
the dm-raid system is not active during the anaconda run, but is
activated before mdadm in the regular startup. DM-raid will detect the
old raid signature and lock the disk, preventing mdadm from using is.
Apart from a complete disk wipe, you can set the 'nodmraid' kernel
parameter in grub to prevent this from happening. Destroying the old
raid-set using the bios tool before installing mdadm often will not
work in my experience.
Roelof
Timmy wrote:
I have installed SL 5.1 many times! The file system can be corrupted
easily! I don't know whether it is RedHat Linux's weakness. Here
are my experiences:
Case 1.
The system might stop here at boot time:
RedHat Nash 5.1.19.......
After rebooting, it might boot normally or the system went corrupted
and no more boot again!
Case 2.
I installed 2 SATA harddisks as mirror pair on a SiI SATA software
RAID card. Installation is successful but after several days'
operation, the system could not read the RAID pair. Formatting was
needed.
Case 3.
After several days' downloading of a movie file through Ktorrent, the
file system went corrupted again! Formatting harddisk required.
I heard that downloading BT file hurts hard disk very much. However,
Case 1 and Case 2 do not have any relationship with BT task.
Any technique or trick to avoid this?
