alpha newbie question

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alpha newbie question

Nick Smith-2
i just got my first alpha box, its an alpha server 400, i have 3x9gig
scsi drives in it. i was wondering if you can boot off of raid5 or
even raid1? i know some of my sparc's had a problem with it, but this
is new territory for me.

thanks for the help

Nick

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Re: alpha newbie question

Bryan Østergaard
On Wed, Mar 01, 2006 at 10:33:41PM -0500, Nick Smith wrote:
> i just got my first alpha box, its an alpha server 400, i have 3x9gig
> scsi drives in it. i was wondering if you can boot off of raid5 or
> even raid1? i know some of my sparc's had a problem with it, but this
> is new territory for me.
>
That should work fine using a hardware raid controller. If using
software raid I'd recommend against using raid on /. Even if you can
apply some hackish solution to make it boot the bootloader won't
understand software raid so it can only be a hack. / isn't worth all
that trouble in my opinion as it can easily be rebuilt if needed.

Instead, protect /home and other important data (mail, websites, ..)
using raid but leave the system non-raided and simple.

All this is meant as a general advice and applies to all archs, not just
alpha or sparc.

Hope this helps.

Regards,
Bryan Østergaard
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Re: alpha newbie question

Andrew Gaylard
[hidden email] wrote:

>That should work fine using a hardware raid controller. If using
>software raid I'd recommend against using raid on /. Even if you can
>apply some hackish solution to make it boot the bootloader won't
>understand software raid so it can only be a hack. / isn't worth all
>that trouble in my opinion as it can easily be rebuilt if needed.
>  
>

Surely, all the bootloader needs to know about is /boot?
On my alpha I had no end of trouble trying to use XFS for /,
until I realised that the bootloader only understood ext2.
The solution was to make a separate ext2 partition for /boot,
put the kernels there.

In this way, the bootloader can find the kernels and load them,
and the kernels know how to mount / as type XFS.

Surely similar reasoning applies to software RAID?
(I haven't tried it, but I am very curious to know...)

Now an unrelated question:  can I add IDE disks to my 433au
(Miata)?  If so, are there certain types that are recommended?
Are there any limitations? (e.g. must I boot off SCSI disks?)

Also, under Tru64, I could make bootable tape backups.
Is there a way to get similar functionality in Linux?

Thanks,
Andrew.
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Re: alpha newbie question

Ben de Luca-2

On 02/03/2006, at 9:40 PM, Andrew Gaylard wrote:

> [hidden email] wrote:
>
>> That should work fine using a hardware raid controller. If using
>> software raid I'd recommend against using raid on /. Even if you can
>> apply some hackish solution to make it boot the bootloader won't
>> understand software raid so it can only be a hack. / isn't worth all
>> that trouble in my opinion as it can easily be rebuilt if needed.
>>
>>
>
> Surely, all the bootloader needs to know about is /boot?
> On my alpha I had no end of trouble trying to use XFS for /,
> until I realised that the bootloader only understood ext2.
> The solution was to make a separate ext2 partition for /boot,
> put the kernels there.
>
> In this way, the bootloader can find the kernels and load them,
> and the kernels know how to mount / as type XFS.

there is the usual  root  on raid how toos about. The kernel has to  
know what the raid set is, I havnt tried this on alpha but seeing you  
cant read the raidtab in etc its auto detected from the partion and  
disks. I dont know if the partioning that you need to use in alpha  
supports it? Maybe you can pass the kernel this info at boot.

> Now an unrelated question:  can I add IDE disks to my 433au
> (Miata)?  If so, are there certain types that are recommended?
> Are there any limitations? (e.g. must I boot off SCSI disks?)

I have a 433au without a scsi controller so I am sure it can boot off  
ide. I had problems with 2.4 running IDE disks when I was using a  
miata specific kernel. Generic worked fine though. Lots of messages  
about interrupts. I havn't turned my alpha on for a few years so  
maybe its fixed.


> Thanks,
> Andrew.
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Re: alpha newbie question

Nick Smith-2
> > Surely, all the bootloader needs to know about is /boot?
> > On my alpha I had no end of trouble trying to use XFS for /,
> > until I realised that the bootloader only understood ext2.
> > The solution was to make a separate ext2 partition for /boot,
> > put the kernels there.
> >
> >
well i just followed the handbook and created sda1 = swap and sda2 = ext3 = /

does this mean im wasting my time on this very slloooow install and
that its not even going to boot when im finished? or does the boot
loader see ext3 as well?

also i thought that it saw all my drives, but the bios ( or what alpha
calls a bios ) see's all 3 9gig drives, but gentoo only see's sda,
when i went looking in /dev/ it only has the nods for sda and sda1 and
sda2 for some reason, i found a tips and tricks on the gentoo.org
website on how to make raid nods, but that didnt seem to work for sdb
and sdc.  is this normal for alpha to only see the first drive? is
there a way to make the nods to actually make use of the other drives
in the system?

thanks

nick

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Re: alpha newbie question

Andrew Gaylard
Nick Smith wrote:

>>>Surely, all the bootloader needs to know about is /boot?
>>>On my alpha I had no end of trouble trying to use XFS for /,
>>>until I realised that the bootloader only understood ext2.
>>>The solution was to make a separate ext2 partition for /boot,
>>>put the kernels there.
>>>
>>>
>>>      
>>>
>well i just followed the handbook and created sda1 = swap and sda2 = ext3 = /
>
>does this mean im wasting my time on this very slloooow install and
>that its not even going to boot when im finished? or does the boot
>loader see ext3 as well?
>
>also i thought that it saw all my drives, but the bios ( or what alpha
>calls a bios ) see's all 3 9gig drives, but gentoo only see's sda,
>when i went looking in /dev/ it only has the nods for sda and sda1 and
>sda2 for some reason, i found a tips and tricks on the gentoo.org
>website on how to make raid nods, but that didnt seem to work for sdb
>and sdc.  is this normal for alpha to only see the first drive? is
>there a way to make the nods to actually make use of the other drives
>in the system?
>  
>

I don't know if the bootloader can boot off ext3 partitions; I've never
tried.  You'll have to dig into the docs to find out.

To resolve SCSI problems, check if the kernel can see your devices by
looking at the output of "dmesg".  If it shows all devices, then you're
nearly there.  But if not, missing device nodes are the least of your
problems.  And no, it is not normal for only the first drive to be seen;
I have two drives both of which have always shown up in dmesg.

So please post the relevant bits of dmesg output, including the SCSI
controller and all devices.

I'd try to partition your sdb and sdc, make filesystems on them, and
copy lots of data onto them to ensure that the hardware's behaving.
After all, this machine was probably built in the last millenium.
Only if that works would I try to get RAID working (and I'd try just
striping or mirroring sdb and sdc on their own first, before attempting
the / filesystem).

Andrew.
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Re: alpha newbie question

Ben de Luca-2
>
> I don't know if the bootloader can boot off ext3 partitions; I've  
> never
> tried.  You'll have to dig into the docs to find out.

ext3 is ext2 with a journal. so if it can see ext2 it can see ext3
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Re: alpha newbie question

Nick Smith-2
In reply to this post by Andrew Gaylard
>
> I don't know if the bootloader can boot off ext3 partitions; I've never
> tried.  You'll have to dig into the docs to find out.
>
> To resolve SCSI problems, check if the kernel can see your devices by
> looking at the output of "dmesg".  If it shows all devices, then you're
> nearly there.  But if not, missing device nodes are the least of your
> problems.  And no, it is not normal for only the first drive to be seen;
> I have two drives both of which have always shown up in dmesg.
>
i forgot to post that dmesg only reports sda, but why would there only
be sda, sda1 and sda2 in /dev? i would think there would be more
"incase" you get more drives.

> So please post the relevant bits of dmesg output, including the SCSI
> controller and all devices.
>
> I'd try to partition your sdb and sdc, make filesystems on them, and
> copy lots of data onto them to ensure that the hardware's behaving.
> After all, this machine was probably built in the last millenium.

yeah i thought about that, originally the machine had 3x1gig scsi
drives in it, i took them out and replaced them with newER 9gig
drives, all working and in good condition, they were pulled from other
working machines.

> Only if that works would I try to get RAID working (and I'd try just
> striping or mirroring sdb and sdc on their own first, before attempting
> the / filesystem).

yeah im going to leave the root/boot drive alone, but i would like to
get redundancy on at least sdb and sdc if i can get them working.

so what is the next step since dmesg doesnt show the drives? im just
the ID's are correct and not conficting.  the machine bios does see
the drives.  i havnt figured out a way to get into the card bios yet,
on an intel machine you have the option of hitting F6, nothing like
that shows on the Alpha machine....

>
> Andrew.
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>
thanks for all your help thus far.

Nick

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Re: alpha newbie question

Nick Smith-2
In reply to this post by Ben de Luca-2
On 3/2/06, Ben de Luca <[hidden email]> wrote:

> >
> > I don't know if the bootloader can boot off ext3 partitions; I've
> > never
> > tried.  You'll have to dig into the docs to find out.
>
> ext3 is ext2 with a journal. so if it can see ext2 it can see ext3
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>
good i feel a little better about continuing the install then, just
have to get those other drives working and ill be all set.
thanks

Nick

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Re: alpha newbie question

Andrew Gaylard
In reply to this post by Nick Smith-2
Nick Smith wrote:

>so what is the next step since dmesg doesnt show the drives? im just
>the ID's are correct and not conficting.  the machine bios does see
>the drives.  i havnt figured out a way to get into the card bios yet,
>on an intel machine you have the option of hitting F6, nothing like
>that shows on the Alpha machine....
>  
>
This sounds like a SCSI problem.  You'll have to check IDs,
cabling, termination, host adapter firmware, the whole lot.

Try connecting one drive at a time and see what the kernel
displays.  I've seen a faulty SCSI device prevent the whole chain
from working.

I doubt that it's a kernel problem, since one drive is detected.
If *no* drives were detected, then I'd suspect the kernel.
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Re: alpha newbie question

Marc Giger
In reply to this post by Nick Smith-2
Hi,

On Thu, 2 Mar 2006 09:42:35 -0500
"Nick Smith" <[hidden email]> wrote:

> On 3/2/06, Ben de Luca <[hidden email]> wrote:
> > >
> > > I don't know if the bootloader can boot off ext3 partitions; I've
> > > never
> > > tried.  You'll have to dig into the docs to find out.
> >
> > ext3 is ext2 with a journal. so if it can see ext2 it can see ext3
> > --

Wow, 10 mails in one day! Is this a new record for this list?:-)

I just want to say that it is relatively easy to boot from a software
raid1. Since the discs are bitwise mirrored, you can mount a single
partition directly. This is also the trick behind booting from a raid0
array. It doesn't boot from raid but reads just a single partition from
the raid. I should mention that you shouldn't mount a part from the
array read-write...

My setup is as following:

/dev/md0 on / type xfs (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
udev on /dev type tmpfs (rw,nosuid)
devpts on /dev/pts type devpts (rw)
/dev/md5 on /boot type ext2 (rw)
/dev/md1 on /usr type xfs (rw)
/dev/md2 on /var type xfs (rw)
/dev/md3 on /home type xfs (rw)
/dev/md10 on /usr/portage type xfs (rw,noatime)
/dev/md11 on /space/01 type xfs (rw,noatime)
/dev/md12 on /space/02 type xfs (rw,noatime)
/dev/md13 on /space/03 type xfs (rw,noatime)
none on /dev/shm type tmpfs (rw)

(swap is mirrored too)

My boot partition is ext2 (to make aboot happy) and about ~40MB in size.
ext3 doesn't make sense, because the journal also needs space but
would work too...

If one disk fails, I have no downtime and loose no data.

I hope this helps a little bit with your decisions.

greets

Marc
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