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Here is a summary of some fun I've recently had with Sun and a new V880.

I got the machine and put a Sun Ultra-3 card in it attached to a SDLT 320
Sun drive - I wanted fast backups as it contained 6 x 72Gb drives.

As the internal drives are not hardware RAID-5 and I wanted resilience, I
decided to go for Solaris 9's Disksuite aka Sun Volume Manager and would
mirror the disks. Even though they are on the same controller, this would at
least help with disk failures.

All fine so far - installed Solaris 9, latest patches etc, then configured
DiskSuite to mirror root and the other disks.

Stuffing a SDLT tape in the drive, I excitedly ran a ufsdump on all the UFS
filesystems and waited... And waited... I discovered I was getting 4Mb/s
backup speeds even on slices with large Oracle files (approx 35Gb).

Hmm -not good. Luckily we had Sun Gold Support so logged a call and received
a helpful chap who, after getting all the relevant details i.e. Explorer
files etc, said that the problem was that I was doing a UFS dump with the
filesystem mounted and that Sun didn't recommend that.

I asked if he was serious and he suggested that if I unmounted the
filesystems, I could get a proper backup. What about / I inquired - how do I
do that? Well, if you boot off a CD, you can back up the system that way? So
if I want to back up a Sun system, I have to drop to single user mode and
manually run a ufsdump command! What a load of tosh! He was persisitant and
stuck by his guns insisting that was the problem!

In the meantime - I had been doing some experimentation myself and
discovered that if I turned on logging and changed the mirroring read
strategy from round-robin to geometric, I got backup read speeds of between
10Mb/s to 30Mb/s (compressed)!

The moral is - do Sun really want to keep their customers by telling them
that the only way to backup a system is to stand by it and load CD's then
manually type the commands in? If someone from Sun is reading this - you
really need to get your people-facing guys sorted! IBM, Apple, HP and
Microsoft would be pissing themselves if this was the only way they
recommended people to backup their systems!!

On Wed, 21 Jul 2004, Nigel P. Longbottom wrote:

> Hmm -not good. Luckily we had Sun Gold Support so logged a call and received
> a helpful chap who, after getting all the relevant details i.e. Explorer
> files etc, said that the problem was that I was doing a UFS dump with the
> filesystem mounted and that Sun didn't recommend that.
>
> I asked if he was serious and he suggested that if I unmounted the
> filesystems, I could get a proper backup. What about / I inquired - how do I
> do that? Well, if you boot off a CD, you can back up the system that way? So
> if I want to back up a Sun system, I have to drop to single user mode and
> manually run a ufsdump command! What a load of tosh! He was persisitant and
> stuck by his guns insisting that was the problem!

IF you backup a file system while it is busy, how do you expect
it to be reliable and consistant? However, using UFS snapshots
might help in this scenario.

> In the meantime - I had been doing some experimentation myself and
> discovered that if I turned on logging and changed the mirroring read
> strategy from round-robin to geometric, I got backup read speeds of between
> 10Mb/s to 30Mb/s (compressed)!

Very good. Now, what has that got to do with backups?

> The moral is - do Sun really want to keep their customers by telling them
> that the only way to backup a system is to stand by it and load CD's then

Who on earth seriously uses CDs as a backup medium?

> manually type the commands in? If someone from Sun is reading this - you

Manually? No, sysadmins with a clue use a script, preferably
driven from cron.

> really need to get your people-facing guys sorted! IBM, Apple, HP and
> Microsoft would be pissing themselves if this was the only way they
> recommended people to backup their systems!!

Or perhaps you could purchase some 3rd party application, like
Veritas, to perform your backups.

And I'm sure a datacenter manager would be pissing himself if you
told him you wanted to backup a multi-GB file system using CDRWs...
Well, after he fired you, anyway.

--
Rich Teer, SCNA, SCSA

President,
Rite Online Inc.

Voice: +1 (250) 979-1638
URL: http://www.rite-online.net

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Rich Teer <rich.teer@rite-group.com> writes:
>On Wed, 21 Jul 2004, Nigel P. Longbottom wrote:

>Very good. Now, what has that got to do with backups?

>> The moral is - do Sun really want to keep their customers by telling them
>> that the only way to backup a system is to stand by it and load CD's then

>Who on earth seriously uses CDs as a backup medium?

I think you misread that. He is talking about booting from CD so
that he can backup with the filesystems unmounted. That's where the
"load CD's" part comes in.

>> manually type the commands in? If someone from Sun is reading this - you

>Manually? No, sysadmins with a clue use a script, preferably
>driven from cron.

If you are first booting from the install CD's then it isn't going to
be easy with cron. Either the OP was given poor advice, or he
misinterpreted the advice he was given. I cannot tell which.

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On Wed, 21 Jul 2004 22:30:59 +0000, Rich Teer wrote:
> On Wed, 21 Jul 2004, Nigel P. Longbottom wrote:
>> Hmm -not good. Luckily we had Sun Gold Support so logged a call and received
>> a helpful chap who, after getting all the relevant details i.e. Explorer
>> files etc, said that the problem was that I was doing a UFS dump with the
>> filesystem mounted and that Sun didn't recommend that.
>>
>> I asked if he was serious and he suggested that if I unmounted the
>> filesystems, I could get a proper backup. What about / I inquired - how do I
>> do that? Well, if you boot off a CD, you can back up the system that way? So
>> if I want to back up a Sun system, I have to drop to single user mode and
>> manually run a ufsdump command! What a load of tosh! He was persisitant and
>> stuck by his guns insisting that was the problem!
>
> IF you backup a file system while it is busy, how do you expect
> it to be reliable and consistant? However, using UFS snapshots
> might help in this scenario.

Yes, that's true, I understand "fssnap" can be used to get a reliable and
consistent backup for ufs filesystems, but...

In this case, he has actually mirrored everything, right? He said
"...configured DiskSuite to mirror root and the other disks."

What about if he were to "metaoffline" his mirrors? One at a time, natch.
Couldn't he then get a backup of a static "offline" mirror? Then when he
puts the mirror back "metaonline" then it will sync up again. The man page
for metaoffline even suggests this as a mechanism for doing online backups!

I can't see any extra risk here, except perhaps on the "work in progress"
while he has 1/2 mirror offline. If he loses one of the disks, he will
either have the "static copy", i.e. like after restoring backup, or he
will have the "real" dynamic copy, and he just syncs a new mirror.

Wouldn't that work? I'm planning to do this myself. Soon! Priorities...
In my case, I'm going around and mirroring all my root disks, and
then I'll be able to use the offline/online trick to get a clean
backup of / filesystem. The other ones I think I can umount, selectively.

--
Juhan Leemet
Logicognosis, Inc.

Rich Teer <rich.teer@rite-group.com> writes:

> And I'm sure a datacenter manager would be pissing himself if you
> told him you wanted to backup a multi-GB file system using CDRWs...
> Well, after he fired you, anyway.

I think you missed his point. He was complaining about the Sun rep's
advice to boot off of a CD so that he could backup the root filesystem
while it was unmounted.

The tone was subtle :-), but I don't think he was agreeing with that
advice.

tim

At Wed, 21 Jul 2004 21:31:46 +0100, "Nigel P. Longbottom" <not@all.valid> writes:

> Luckily we had Sun Gold Support so logged a call and received
> a helpful chap who, after getting all the relevant details i.e. Explorer
> files etc, said that the problem was that I was doing a UFS dump with the
> filesystem mounted and that Sun didn't recommend that.
>
> I asked if he was serious and he suggested that if I unmounted the
> filesystems, I could get a proper backup.

You have Sun Gold support. You have the right to competent advice,
but you're not getting it. Sounds like you should be going up the
management chain on this one. You wouldn't be doing Sun any favors by
letting this sort of service go without complaint.

If you'd like better advice about how to do backups of Oracle on
Solaris, you might start with the Sun Blueprint series of
best-practice documents. E.g., see Art Licht's paper
<http://www.sun.com/blueprints/0802/816-7395-10.pdf> and Selim Daoud's
<http://www.sun.com/blueprints/0702/816-5243-10.pdf>.

On Wed, 21 Jul 2004, Neil W Rickert wrote:

> I think you misread that. He is talking about booting from CD so
> that he can backup with the filesystems unmounted. That's where the
> "load CD's" part comes in.

AH yes, that makes more sense. Thanks for the (obviously needed!)
interpretation!

--
Rich Teer, SCNA, SCSA

President,
Rite Online Inc.

Voice: +1 (250) 979-1638
URL: http://www.rite-online.net

On Wed, 21 Jul 2004, Juhan Leemet wrote:

> Yes, that's true, I understand "fssnap" can be used to get a reliable and
> consistent backup for ufs filesystems, but...
>
> In this case, he has actually mirrored everything, right? He said
> "...configured DiskSuite to mirror root and the other disks."
>
> What about if he were to "metaoffline" his mirrors? One at a time, natch.
> Couldn't he then get a backup of a static "offline" mirror? Then when he
> puts the mirror back "metaonline" then it will sync up again. The man page
> for metaoffline even suggests this as a mechanism for doing online backups!

Yes, that would also work. Off the top of my head, I'm not sure
what all the pros and cons of fssnap vs metaoffline are, although
one obvioous benefit of the latter is that it'll work with any
file system, not just UFS (IIRC, only UFS supports fs snapshots
at present. I would be very surprised if DFS didn't, unless it
wasn't necesary by design...).

> I can't see any extra risk here, except perhaps on the "work in progress"
> while he has 1/2 mirror offline. If he loses one of the disks, he will
> either have the "static copy", i.e. like after restoring backup, or he
> will have the "real" dynamic copy, and he just syncs a new mirror.

True. And this risk can be mitigated by using 3-way mirrors.
That way, when you break off one of the sub-mirrors to back it
up, the "live" file system is still safe in a 2-way mirror.
It's one of those cost/benefits type of things.

--
Rich Teer, SCNA, SCSA

President,
Rite Online Inc.

Voice: +1 (250) 979-1638
URL: http://www.rite-online.net

On Wed, 21 Jul 2004 21:31:46 +0100 "Nigel P. Longbottom" <not@all.valid> wrote:
> In the meantime - I had been doing some experimentation myself and
> discovered that if I turned on logging and changed the mirroring read
> strategy from round-robin to geometric, I got backup read speeds of between
> 10Mb/s to 30Mb/s (compressed)!

What is the geometric strategy? (use knowledge of proximity of last read
to last known head position?)

/fc

On 22/7/04 7:03 am, in article m3k6wwd1dq.fsf@magma.savecore.net, "Frank
Cusack" <fcusack@fcusack.com> wrote:

> On Wed, 21 Jul 2004 21:31:46 +0100 "Nigel P. Longbottom" <not@all.valid>
> wrote:
>> In the meantime - I had been doing some experimentation myself and
>> discovered that if I turned on logging and changed the mirroring read
>> strategy from round-robin to geometric, I got backup read speeds of between
>> 10Mb/s to 30Mb/s (compressed)!
>
> What is the geometric strategy? (use knowledge of proximity of last read
> to last known head position?)
>
> /fc

Thanks for the response. After Richard's comments, I'm glad some people
jumped in to clarify. Don't worry - I'm not that bad to start backing up to
CD-RW and yes - my tone can be a bit subtle!

I suppose my real point was a dig at Sun support. My initial query was about
backup rates to tape but I ended up being told that the problem was due to
mounted filesystems. With the competition in UNIX markets, I would say Sun
is damaging itself by saying not to backup while filesystems are mounted
(and they were adamant about this). I've been doing this for years
(obviously while the filesystems are quiet i.e. Oracle is shut down and the
servers are not active 24x7) and have no problems when restoring from these
backups in a Disaster Recovery exercise.

The other systems I work on - namely IBM AIX are quite happy to suggest you
backup when the filesystems are 'quiescent' (as they happily term it).

As for geometric read strategy - it's one of the options that you can assign
to mirrors using the metaparam command. Its recommended if you have large
sequential reads.