Re: Offline defrag
- From: "John Smith" <flava_kid@xxxxxxxxxxx>
- Date: Mon, 11 Sep 2006 13:19:21 +0100
it is a company policy that we are able to restore message / folders as
quick as possible, that is why we have invested a lot of money on disk
staging systems. we keep the exchange backup on disk for a week for the
images are expired. I am trying to trace what is causing the backup
performance hit. at the moment we are think it has something to do with
exchange.
however there is noway to prove this, if there was overall system
performance, a lot of users would have complained. at the moment the
throughput is less then 1 meg for brick level backup and 6meg for IS
backup. backing up 680gig database at the speed will never finish in time.
we have imposed storage limits, but people already have huge mailboxes.
how can I do some test to make sure everything in exchange - disk speed,
network link throughput, read/writes of disk system - is working fine
without dismounting the stores.
I didn't quite understand this "(but white space is not backed up during
brick-level backup)." but are they backup during IS backup, I think they are
backup on full IS backup.
Online defragmentation is always terminated according to the event log, this
may have something to do with backup schedule times, can I run online defrag
during the day and how much performance hit am I looking if I was to attempt
this.
"Kirill Palagin" <kpalagin@xxxxxxxxxxxxxxxxx> wrote in message
news:%23XpmodZ1GHA.4264@xxxxxxxxxxxxxxxxxxxxxxx
Brick-level backup is infamous for being slow, redundant and troublesome
(but white space is not backed up during brick-level backup).
Switch to Store backup and you may get 30GB/h and up transfer rates. After
performing successful online backup you can worry about reducing white
space (you can only reduce it, but never eliminate). You can reduce it
either with the help of ESEUTIL or by moving mailboxes to the other
database, whacking .edb+stm, moving mailboxes back. I strongly recommend
ESEUTIL approach.
I also would suggest imposing storage limits.
File-system defrag will not make a difference because database access is
random by nature, not sequential.
John Smith wrote:
we have roughly about 500 users, the last backup took 58hrs to complete
and it didn't backup all the storage groups. we are performing a brick
level backup. To give some idea on how our backup works, we backup to
disk over night, and in the morning this is staged off to tape. however
we have not had a successful backup for couple days because the
throughput is sooo slow. sometimes we see multiple backup schedule
running because the last backup didn't complete the allocated backup
window.
just to make things clear, the total sum of our database are 680gig, our
biggest database 210gig with 150gig whitespace ( Ouch ). the rest of the
database are between 50-100gig and each database has roughly 12gig of
whitespace. Going through the event log and filtering for event id 1221
and adding up all the whitespaces, we can roughly save 230gig of space
and reduce the databases of 380gig total.
I can handle the whitespace issue if the backup performance is quicker,
but at the moment backup is slower than snail with arthritis.
can I also ask if file system defrag would improve anything, if so, would
this require the stores to be dismounted.
"Kirill Palagin" <kpalagin@xxxxxxxxxxxxxxxxx> wrote in message
news:ODv0vFZ1GHA.1288@xxxxxxxxxxxxxxxxxxxxxxx
Having 10GB of whitespace in databases this big should is expected and
should not be cause for offline defrag.
How many users you have and how long backup takes? Hopefully, you are
not doing brick-level backup.
John Smith wrote:
Hi all,--
I am new to exchange, we have recently migrated from lotus notes, where
users had unquoted mail files. When we have moved to exchange 2003, we
have decided to introduce quota with the mail system. so we've created
couple mail stores - 8 in total - and moved users about.
since we've moved users about, out database grew from 370gig to 680gig.
I have checked the event log and there is a lot 1221 event id, it seems
that each mail store has approximately 10gig of free space.
the other thing, our backup has also taking hit, it is extremely slow,
it takes forever to backup. the exchange through put for the backup has
takes a huge performance hit. I think the backup time interferes with
online defrag, I know the obvious thing to do is run the backup another
time, but because of the size of the databases being backed it is
continuously backing 24/7.
I have heard about eseutil, but alot of people are advising against it,
I don't have a recent backup either, I want to fix all this issues
before it becomes a nightmare.
please advice.
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Text from most Windows dialogs can be copied to clipboard with Ctrl-INS.
Free productivity applications suit - www.openoffice.org
Free Internet calling - www.skype.com
Free SQL database Firebird - full support for transaction control,
triggers, stored procedures, partial SQL-99 compliance
http://www.ibphoenix.com/main.nfs?a=ibphoenix&s=1142758270:704186&page=what_is_interbase
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