OT: os/hardware recommendations (was Re: filepro RAM limit)

[Brian K. White]

----- Original Message ----- 
From: "Jay R. Ashworth" <jra at baylink.com>
To: <filepro-list at lists.celestial.com>
Sent: Sunday, May 13, 2007 10:12 PM
Subject: Re: OT: os/hardware recommendations (was Re: filepro RAM limit)


> On Sat, May 12, 2007 at 03:19:01AM -0400, Brian K. White wrote:
>> I suppose I should clarify that this recommendation is only in the 
>> assumed
>> context that the old box was only a single scsi drive on a 80 or 160 mhz
>> cable. Any userbase/workload that currently functions at all, however
>> slowly, on that, is automatically small enough that 4 sata's (even plain
>> sata-1 150mbit ones) and software raid5 on linux will be fine, will in 
>> fact
>> be not just fine but ridiculously faster. If you have 50 or more users 
>> and
>> the application is very active then a hardware raid card and more disks 
>> are
>> in order. Can still be sata though, though sata-II (300mbit with command
>> queueing) would be a good idea.
>
> Note that recovering Linux systems with the boot and root volumes on
> software raid can be problematic.

I always put /boot on a small raid1. So every disk in the array has an 
identical copy of the small ext2 partition with the boot files.
Any disk in the array can boot by itself and has the necessary kernel 
modules for mounting the rest of the arrays either in initrd or in the 
kernel itself.
Easy.

Restoring is a large topic.

I'm still working on the simplest complete restore-from-tape procedure, 
though it's just fine-tuning for the sake of being a perfectionist.
Backupedge can't provide a recoveredge disk for some of my systems. It 
does't say why exactly.
They are just regular opensuse 10.x with various combinations of reiserfs, 
ext3, ext2*, hardware LSI raid, software raid, 64bit, 32bit. But nothing 
really custom, no custom kernels or disk layouts that were created outside 
of the installer. Yast does kernel and grub updates without breaking 
anything for example.
But Backupedge doesn't claim to officially support suse specifically so 
thats fair.

Basically restoring just isn't as much of an issue for me lately. I have a 
recipe I follow for fresh installs that I'm always improving that is down to 
less time than ctar/backupedge might take sometimes anyways.

Given an install disk or a knoppix disk _I_ at least can do a restore pretty 
quickly onto the same or different hardware. Without backupedges magic, I 
don't have a good way to make that fast or simple for anyone else. There are 
a slew of linux backup solutions I still need to investigate.
Linux magazine has an article this month on a special purpose live cd called 
"System Rescue CD" that looks good,
and LinuxPro magazine has one on Mondo, which I've been meaning to try out 
for a while.
Things like Amanda and Bacula seem to have never heard of the KISS 
principle. A good friend of mine is on the bacula devel team and I was just 
at his place for the weekend (for his kids birthday, and got to hang out 
with dj from djgpp!), and watching even _him_ run off some backups to tape 
it looked like more fuss and more special things that the user must know 
about than should be necessary. Too easily screwed up. Perhaps it can be 
configured to operate simply and merely also has the option of being 
complex, (and apparently defaults that way too).

So in the meantime I just do backupedge backups, which gets full easy 
recoveredge cd's for some boxes at least, and for the others I just do a 
fresh text only minimalist install, which goes very fast, using the suse 
installer to configure new drives, which is no harder than using backupedge 
to do it IMO. I maintain my own install source which includes the backupedge 
rpm which I can select right during initial install too, then use that to 
restore the tape. Or boot to knoppix and install backupedge to ram and run 
that to restore from tape.

A couple boxes I even made my own usb boot sticks (little $7 64M staples 
ones) with the suse installer all preconfigured with the xml file that the 
"clone this system?" question at the end of an install creates.
In those cases you just stick the usb stick in, boot up, and it dos a fresh 
install, but with all the choices preconfigured, one of those includes 
installing backupedge from a copy I keep on my own install source, so once 
that runs I can just run the installed backupedge to restore from tape.

Really the most difficult thing about restoring a linux box (software raid 
or any other disk system) is that there are so many ways to do it.

Brian K. White    brian at aljex.com    http://www.myspace.com/KEYofR
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