grub installation of lacking grub on the CPU-GPU raid1 machine (gig64) by
the command
grub-install /dev/sdb
was successful (Installation finished. No error reported) with either the
two victim 250GB disks and then with the two 1000GB disks.
I can't explain my failure to do so in the recent past.
The pipe command that I described before proved equivalent to what you
described, i.e., physically testing whether grub is installed, each disk at
a time.
Thanks a lot
francesco
-- Forwarded message --
From: Francesco Pietra chiendar...@gmail.com
Date: Tue, Oct 8, 2013 at 5:11 PM
Subject: Re: Debian installer and raid0
To: debian-users debian-u...@lists.debian.org, amd64 Debian
debian-amd64@lists.debian.org
I hope not to bother beyond the limit, but the security of mirror raid is
something of utmost importance, at least in my work of biochemist, with
very limited ability in recovering from disk failures.
I planned to use the double-opteron, two sockets, server, tya 64, as a
victim for the test you suggested. However, the test
root@tya64:/home/francesco# dd bs=512 count=1 if=/dev/sda 2/dev/null |
strings
ZRr=
`|f
\|f1
GRUB
Geom
Hard Disk
Read
Error
root@tya64:/home/francesco# dd bs=512 count=1 if=/dev/sdb 2/dev/null |
strings
ZRr=
`|f
\|f1
GRUB
Geom
Hard Disk
Read
Error
suggested that grub was installed on both disks. Using one disk at a time,
as you suggested, was in accordance.
Then I carried out the pipe test with the recent machine, gig64:
root@gig64:/home/francesco# dd bs=512 count=1 if=/dev/sda 2/dev/null |
strings
ZRr=
`|f
\|f1
GRUB
Geom
Hard Disk
Read
Error
root@gig64:/home/francesco# dd bs=512 count=1 if=/dev/sdb 2/dev/null |
strings
root@gig64:/home/francesco#
indicating that grub is installed on sda only. Confirmed by using one disk
at a time.
500GB disks on tya64 came from a dismissed doubleOpteron four socket server
that I had assembled several years ago. Probably at that time in my
activity as a biochemist I was left more time to be careful about linux.
With gig64 the two 1000GB disks came recently from the store and the
described failure as to installing grub on sdb was with them. Unless the
problem is different, related to the particular gig64 machine.
QUESTIONS:
(1) If there is any chance that the particular hardware of gig64,
comprising two GPUs (I called gig64 a server, while, unlike the real server
tya64, it is a consumer mainboard GA-X79-UD3 with Intel(R) Core(TM)
i7-3930K CPU @ 3.20GHz and two GTX680 GPUs, leading to very fast number
crunching, NOT overclocked) can interfere with installation of grub on the
second disk, it seems to me that gig64 is the appropriate victim. However,
by replacing the two 1000GB disks with two spare victim disks that I should
have somewhere (amd64 on both, and likely grub too). If anything, linux is
unable to tell anything about the GPUs (and even nvidia-smi tools tell very
little, which my lend suspicion on why the grub installation of the second
disk failed). Fundamentally, it is a game machine, so that no chance to get
mirror raid even mentioned by bloggers of this type of computers.
(2) Is the above pipe test (that grub installed leads to some message when
failure is encountered, while no message means no grub available) always
reliable and equivalent to detaching disks?
thanks
francesco
On Mon, Oct 7, 2013 at 10:38 PM, Bob Proulx b...@proulx.com wrote:
Francesco Pietra wrote:
I forgot asking naively how to boot safely to the grub menu.
Press a key on the keyboard before the 5 second count down timer
counts all of the way down. Pressing a key stops the timer and causes
it to stay on the menu waiting for keyboard input.
Bob
