Amanda-Users

Re: Speed up 400GB backup?

2004-07-20 17:40:55
Subject: Re: Speed up 400GB backup?
From: "Stefan G. Weichinger" <monitor AT oops.co DOT at>
To: Amanda List <amanda-users AT amanda DOT org>
Date: Tue, 20 Jul 2004 23:37:38 +0200
Hi, Frank,

on Dienstag, 20. Juli 2004 at 07:41 you wrote to amanda-users:

>> 420GB is not the total amount per night. Something is bogging this down
>> though and I don't know what. I am not using holding disks because the
>> majority of data is being backed up from one set of disks to another on
>> the same machine. This one machine has a set of RAID 10 disks. These
>> disks are backed up by amanda and put onto a set of RAID 5 disks. 

FS> OK, I was assuming a different setup.  Having a holding disk would let
FS> you run multiple dumps in parallel.  Wouldn't help much (if any) when
FS> its all on one machine, but can really speed up your overall time if
FS> you have multiple clients.

Given Joshua's note about having data and backup on the same
controller I would just suggest adding a cheap'n'huge IDE-drive (and
controller, if necessary) for a holdingdisk.

This will speed things up locally, too. Think parallel dumping AND the
fact that people could access data at ~normal speed even while the
holdingdisk is still feeding the tape (while this is still not the
solution here, estimates ain't done on the holdingdisk ....)

Having a separate holdingdisk is never a bad thing with AMANDA IMHO.

>> As far
>> as assigning spindle #s goes I don't quite understand why I would set
>> that. I have inparallel set to 4  and then didn't define maxdumps, so I
>> would assume that not more than 1 dumper would get started on a machine
>> at once. Am I getting this right? 

FS> I think maxdumps defaults to 2 but I may be wrong (someone else should
FS> jump in here).

It is 10. ( grep -r "define MAXDUMPS" amanda-2.4.4-p3 )

>> Estimate Time (hrs:min)    7:30

FS> Here's your runtime problem, 7.5 hours for estimates .

Yep.

>> Run Time (hrs:min)        10:35
>> Dump Time (hrs:min)        2:52       0:29       2:23

FS> Three hours for dumps doesn't seem too bad.  It could probably
FS> be improved some, but the estimates are what's killing you.

Yep again.

FS>   As for the estimates, are you using dump or tar?  Look in the
FS> *debug files on the clients and see which one was taking all the time
FS> (I'm guessing venus since it looks like you did a force on bda1).
FS> Does that filesystem have millions of small files?
FS>   I'm not sure of the best way to speed up estimates, other than a
FS> faster disk system.  Perhaps someone else on the list has some ideas.

My idea is to request more details here.

Relevant dumptype-definition, local/remote-info, df venus:/home, etc
...

-- 
best regards,
Stefan



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