Craig White wrote:
On Tue, 2006-03-28 at 08:05 -0700, Craig White wrote:
On Mon, 2006-03-27 at 21:43 -0600, Laurence Vanek wrote:
Greetings -
To my surprise, fresh install of FC5 with RAID 1 configured at install
time went without a hitch. I have /dev/md0 defined on /boot
partitions. It boots fine with this setup.
I had my FC4 system setup this exact way except I found that I had to
manually install grub on one of the disks to permit booting off either
one if the other is down.
Does anyone know of a way to check for the presence of grub on each
drive (obviously its on hda since it boots presently) to see if this
needs to be done for FC5 also without powering down each drive in turn &
attempting to boot?
----
thought I should post against the right thread
just an untested thought...
bb if=/dev/sda of=/tmp/sda-bootblock.bin bs=512 count=1
bb if=/dev/sdb of=/tmp/sdb-bootblock.bin bs=512 count=1
diff /tmp/sda-bootblock.bin /tmp/sdb-bootblock.bin
Thinking...
- substitute different values for sda/sdb as fits
- the first 512 bytes on each drive are the boot (perhaps less, someone
will surely correct me...it might just be the first 256 or 384 bytes)
- if they are the same (i.e. grub has been installed on both), there
will be no diff
otherwise...
grub-install /dev/sdb
Of course, the only way that you'll ever KNOW for sure that it's going
to work is to do a real simulation, i.e. disconnecting one drive, then
the other drive...
----
not only wrong thread but as Paul so correctly points out.
dd - NOT bb
I am rapidly ingesting coffee but haven't figured out a mainline method
so I am left to normal ingestion methods which apparently haven't quite
caught up to my fingers or my brain.
duh.
Sorry
Craig
Craig -
results using bs=466
============
[root@localhost tmp]# dd if=/dev/hda of=/tmp/hda-bootblock.bin bs=466
count=1
1+0 records in
1+0 records out
466 bytes (466 B) copied, 7.6e-05 seconds, 6.1 MB/s
[root@localhost tmp]# dd if=/dev/hdc of=/tmp/hdc-bootblock.bin bs=466
count=1
1+0 records in
1+0 records out
466 bytes (466 B) copied, 7.7e-05 seconds, 6.1 MB/s
[root@localhost tmp]# diff hda-bootblock.bin hdc-bootblock.bin
Binary files hda-bootblock.bin and hdc-bootblock.bin differ
================
files also differ is bs=256, 128
BUT for bs=64 we get no complaint from diff:
================
[root@localhost tmp]# dd if=/dev/hda of=/tmp/hda-bootblock.bin bs=64 count=1
1+0 records in
1+0 records out
64 bytes (64 B) copied, 7.8e-05 seconds, 821 kB/s
[root@localhost tmp]# dd if=/dev/hdc of=/tmp/hdc-bootblock.bin bs=64 count=1
1+0 records in
1+0 records out
64 bytes (64 B) copied, 7.6e-05 seconds, 842 kB/s
[root@localhost tmp]# diff hda-bootblock.bin hdc-bootblock.bin
================
