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Defragging my Exchange Server Stores

Posted on 2006-11-20
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Hi, I have been moving mailboxes, probably 50 +, from one Mailbox Store to another and was wondering if I should perform an offline defrag on the Mailbox Stores.

Also, how often should I perform an offline defrag on the Mailbox Stores?

The reason I bring this up, is I have been experiencing a tremedous increase in backup times.

It is taking upwards of 53 hours to backup my Exchange Server.  I do not take it offline to do backups.

Thanks for any help you can give.

Bob
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Question by:dgriffit55
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kristinaw earned 125 total points
ID: 17979366
Bob, how large are you mailbox stores? Your backups obviously shouldn't be taking that long. If they take that long to backup, how long do they take to do a restore? Are you splitting your backup into separate jobs? That might help as well.

Kris.
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by:dgriffit55
ID: 17979550
Kris,
Our unofficial policy requires me to allow up to 550MB per user, but we have made some exceptions for the President, Vice President and other Deans.  They have 1GB + each.  I am using Symantec Mail Security along with the AntiSpam Premium service too.  I have thought about taking the Exchange Server offline to back it up, but that will not clear out the Log and we are focused on not having any downtime.

Also, a restore on a average mailbox takes approximately 5-10 minutes to restore.  I have never attempted to do a complete restore due to the lack of equipment to perform the mock up.

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by:Sembee
ID: 17979595
The first question is whether you need to.
A defrag of the stores is not recommended by Microsoft as a regular item, I don't do them personally unless...

- I am directed to by Microsoft support
- I have hit the 16gb limit in Exchange 2000 standard edition or older
- I will gain at least 50% of the space back AND there is no chance of that space being used again.

You need to look for event ID 1221 in the event logs overnight. This will tell you how much white space (free space in MS terminology) there is in the store. That is the approximate amount of space that you will get back.

Also bear in mind that it is total downtime of the server, you need around 1.5 times the amount of space of the current database size (so if the db is 20gb you need 30gb in space) and that the process runs along at between 1 and 4gb per hour. So a 20gb store could take between 5 and 20 hours to defrag.

Simon.
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by:kristinaw
ID: 17981133
Simon,

if his backups are taking 53 hours, i doubt his online maintenance is completing at all.

the fact that it is taking 53 hours likely has to do with the fact that it sounds like you're doing brick-level backups, since you mention restoring a single mailbox takes 10 minutes. Most ppl do not do blb backups for this very reason, it just takes too long.

Kris.
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by:mario_andres
ID: 17981405
I do agree with Kris. I run EAS email archiving for my users and I have to defrag all my exchange databases quarterly.  in order to keep them lean and  bellow 20 Gbs.  Archiving  causes lots of white space. The defrag maintenance will not claim all white space.   I What can estimate how much white space I can claim by using ESM.  I would export the Mailbox information into a coma delimiter file, open it in Excel and adding all of the mailbox sizes.  Then What I would do is compare the total size to the EDB file. The syntax that I use is: eseutil /d /p "F:\Exchsrvr\SG04\usersMS02.edb" /t"F:\Exchsrvr\SG04\userssMS021.edb".  This will create a new database file and preserve the old one.
If the process does not complete just simply mount the old database.  Also What I done is to restore the database in my lab environment and compacting it using esefile.exe (  http://support.microsoft.com/kb/192185  ).

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by:kristinaw
ID: 17981712
ok, i didn't mean to imply that i think regular defragging is a good idea. i agree with simon on that point. my point was that if the backup is taking 53 hours, then it may well be interfering with the online maintenance process, which is not a good thing.

kris.
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by:mario_andres
ID: 17981891
Sometimes a defrag is necessary, but let me rephrase my last comment  I do agree with you( Kris ) that the Nightly maintenance may not be completing. I know where Microsoft stands on the defrag issue, but running  defrag with the /t switch, ( preserving the state of the old database )which is very safe, is a good way to reclaim the White space.
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by:kristinaw
ID: 17982301
first off mario, the t command doesn't exactly do what you think it does. all the 't' switch does is allow you to specify the name and path the temporary database is created in. This switch is commonly used in scenarios where the drive that exchange is installed on does not have enough free space hold the temporary database. a temporary database is ALWAYS created, whether you use the t switch or not. if the 't' switch is not used, the temp database will be called tempdfg.edb. The temp database is never copied over the production one until the process has completely finished.

This information is freely available here:
http://support.microsoft.com/kb/158623

so, to get back to the author's original question without all these tangents, i think that an offline defrag is the wrong thing to be concerned about here. BLB backups take a long, long time. Period. I doubt that an offline defrag would help that much anyways.

Reducing the overall size of the edb might help. Ultimately, the backup window should be reduced. I would also check here for more info on online maintenance: http://support.microsoft.com/kb/324358

If the long backup window is interfering with that process, then this is a much bigger concern, imho.

dgriffit, i was more asking about the overall size of your edb file due to the reasoning mentioned above.

kris.
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by:mario_andres
ID: 17983016
Well,  Please do not take this the wrong way.   firs of all I been compacting databases in  exchange 2000 for the past 5 years  and /t switch will create a new database and preserved the old. ( I do this at least once a quarter ) and if you do not have enough space, well can't compact.  A database with good planning can also be compacted out side the production environment and moved back into production.  in matter of fact this the preferred way, This way you will find out how much white space there is.

Back to the problem:

1). If the backup are taking two long well let start on the network/ NICS ?  
2). Let look at the Server resources
3). are they brick level? (to me useless)
4 ) lets look at the backup unit and it s network resources and to what others jobs may be running around the same time.

and gain I am not recommending defrag unless you can determine the amount of white space on the database.
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by:kristinaw
ID: 17983336
woops. looks like i posted the wrong link for eseutil,

http://support.microsoft.com/kb/317014

and if you don't have enough space locally to defrag, you can use the t switch to send the temp database to a different path. despite what you may have done, this is what it was designed for.

kris.
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by:mario_andres
ID: 17983756
isn't that what I said... I posted the link for how to defrag... two comment ago.

eseutil /d /p "F:\Exchsrvr\SG04\usersMS02.edb" /t"F:\Exchsrvr\SG04\userssMS021.edb". you can use any path....

Bob,

   If you can restore the database on a lab server,  try compacting it there first and see  how much space you can gain.
Please,  if you are doing this in the production environment use  the /t switch as in my example above, because this will save you lots of  headaches.
and it preserved the old edb and stm and  create a new edb and stm files ( on a different path or same drive if you have the space) having a fall back
in case something goes wrong.

The way I've been doing this,  I have my transaction logs in a different folder from my databases, before mounting the new database, I rename this folder and
during the mounting process this folder gets recreated with new logs and chk files to match my new database.  this is crucial when using the /t switch while compacting a database,  because the /t switch creates a new database with a new signature, which will not match the old transaction logs, and down the road if you need to do a restore the old transactions logs will not replay, creating a bigger mess.

Please, also if you have access to the switch where you exchange server is connected,  look at the port statistics
and look for error and collisions. also make sure is full duplex and max speed. you server may say is full duplex
but you may have some mismatch errors on the switch. Also download the Exchange Best Practice analyzer Tool from Microsoft
and run it against your exchange environment, this can shine some light into the issue you are having.

Good luck...  
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Author Comment

by:dgriffit55
ID: 17990706
Ok, I think your correct in saying defragging is not the answer.

priv1.edb = 5.5 GB
priv2.edb = 29.2 GB
pub1.edb = 9.6 GB

My Exchange Server setup:

C: = System Operations
D: = Mailbox Storeage
E: = Logs

Both C & E drives are RAID 0.
D drive is RAID 5
3 GB RAM

I believe we are doing what you call brick-level backups.  I am not totally for sure since I am not in charge of backups.  But since it is "my" Exchange server that is taking so long and interfereing with other server backups, it is my "problem".  Is there another way to perform complete backups?  It is very very important that I am able to recover every mailbox at any given time.

I have recommended we get another Quantum Tape Drive backup solution for the other servers, but I am sure that won't fly right now.

Thanks again.

Bob
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by:dgriffit55
ID: 17990760
Also, the server has a 1 gigabit backbone to the Quantum tape driver backup solution, running Symantec (Veritas) BackUp 10d software.

Other resources:
Symantec Mail Security 5.1 w/ AntiSpam Premium


Also, I keep the Exchange Server online 24/7 - unless I need to reboot it for update completions.

So, I have made the proper adjustments with online maintenance during the backup times.
And I have turned off the Mail Security scanning from within mailboxes, but keep the external scanning on.

Hope that helps.

Bob


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by:mario_andres
ID: 17991327
Please also if yo have regular antivirus on the server make sure it is not scanning the Exchange folders....

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by:mario_andres
ID: 17991351
Bob,

  Brinck level backups take for ever and a day.....
you may want to rethingk your backup strategy.
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by:dgriffit55
ID: 18019438
mario,
I exclude the Exchange folder from Symantec AntiVirus on the Server.

I appreciate your insight to brick level backups, but are there any alternative solutions to brick leve?

Thanks.

Bob
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by:Sembee
ID: 18020152
You haven't posted which version of Exchange you are using.
The alternative is to do an information store only backup. That backups the entire database not the individual items. If you need to recover items then you would use either a recovery server (Exchange 2000) or the Recovery Storage Group (Exchange 2003).

A store of 40gb shouldn't take that long - although it depends on the speed of the tape drive. I have a site that does 100gb in four hours or so on to high speed drives.

Simon.
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by:dgriffit55
ID: 18054912
More info that may help.

I am using Exchange 2003 Enterprise on a Windows 2003 Standard Server.

I talked to our backup guru and discovered we are backing up 165GB in 54 hours to a Quantum Value Loader DLT VS160 tape drive that is using DLTtape VS1 80/160GB tapes with hardware compression turned on.  We are using Symantec Backup Exec 10d in junction with the Quantum on a gigabit backbone.  Apparently, we are backing up everything, mailboxes, OS, etc.

Could this just be expected to take 54 hours because of the mere size of the backup?

Thanks.

Bob
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by:mario_andres
ID: 18055019
I am using a Disk backup solultion ( no tapes thank God)  from from a company named Evault.  http://www.evault.com
I hve 2 terabytes of data wich take all of two hours. ( no brick levels ). Each backup is treated as a full.
BUt their technologies pick up the detal change on the disk.  If I need to restore  a database it takes a little over and hour.  right into a Recovery Storage Group.....
This has really improved my backup response  time.....
another company, which does the same time of backups is called DS3 data vaulting..  http://ds3datavaulting.com/about.htm
Also the beuty of this my backup unit is offsite.  of course have need bandwith. but is all worth it...

Mario


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by:Sembee
Sembee earned 125 total points
ID: 18055149
If you are doing mailboxes and the information store, then you are duplicating matters.
Furthermore, if you are compressing the data as well, that can double the backup time. I try not to use compression if possible.
If you are backing up the entire server, then you are also backing up a lot of data that you just do not need.

Look at this way - in the event of a server failure, what are you going to do? Restore everything from the tape? How are you going to do that if there is no OS? Unless you are doing some kind of bare metal backup (which is done in a different way) you would have to reinstall Windows. That is 2gb of the backup wasted because you will not restore all the little files as there is no point.
Then to restore Exchange you need to install Exchange application. Another good half a gb of data that has been replaced from a CD, not from the backup.

You need to review the backup and backup what you know you will need, not "just in case". The vast majority of the contents of c:\windows and c:\program files does not have to be backed up.

Simon.
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