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chuckp2010

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Exchange transaction log drive running out of space

Hi

Environment: Exchange 2007 SP2 on Windows 2008 Server.

Our backups failed last night for whatever reason and this wasn't picked up. Normally this should be ok as we allow for a couple of days logs, but there were some mbx moves as well so we're possibly going to run out of space today.

We don't want to cause any disruption to users since this is a busy day for us!

Does anyone know how I can "create" more space on the transaction log drive without having to dismount the store etc?

Also, if we were to run a manual backup now, would that lessen the performance of Exchange? Although, to be honest, I don't think we have time for a full backup to complete.

Any help appreciated.
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Barry Gill
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It will impact on performance for sure.
But it is easier for you to run the backup, take the knock on performance and get it done, than to mount another drive, move the files and change the drive numbers...

if you are secure in the knowledge that you will be able to allocate the time to it tomorrow, you could just move the older files out of the log directory to clear up space, then do the move later on with exchange shut down.
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chuckp2010

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Thanks..

I don't think I will have time to run the backup before the drive fills up...is there any way to find out the last commited log and move the preceeding ones without dismounting the store?
another note, if one day's failed backup creates this level of immediate pain for you, you are probably better off going through the pain of moving your log directory anyways.

A really detailed explanation of what you can do is in this link (it also discusses which log files you can move manually and what the dangers are...)
http://www.msexchange.org/articles/Exchange-log-disk-full.html
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Barry Gill
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You could do a Incremental/log backup. That will also clear the logs.
Thanks barralus.

So, when you say store dismount, you mean dismount the store and move the log location via Exchange Management Console?

Or dismount the store, move the logs to somewhere else (since dismounting the store commits everything anyway), and then mount the store again?

I guess the second option is quicker? But I'm not sure about mounting a store and moving logs at the same time, even though they've been commited?

Finally, in respect to keeping the store up and just moving the logs anyway - I understand Exchange only actually uses logs if there's been a crash? Normally, it just reads from the database memory?
If your happy to dismount and remount and not worried about a point in time restore for now then the quickest way would be to turn on circular logging.
Dismounting does commit everything, but you need the logs to be able to restore to a point in time.

As Erik says in the link I posted, use the eseutil on the checkfile to find which files have been commited already and move them to another location. This is NOT MOVING the log file location, it is simply clearing some space.
He talks as if you have ALREADY run out of space, so the store has automatically dismounted. So clear up the space before remounting the store.
Personally I would never mess with log files while the store is mounted. (I have massive phobia's about accidentally breaking things).
So if you can dismount, move a few gigs and then remount, you may be able to buy yourself some time to do a proper cleanup/move...
that is a VERY good point Terry!
Thanks guys - we took the option of a dismount, moved the logs, then mounted again. Luckily, we managed to hold until close of business.

Thanks for all your help!

One further question:

> "You could do a Incremental/log backup. That will also clear the logs"

I thought only a full backup cleared the logs?
This should explain it for you..

http://technet.microsoft.com/en-us/library/aa997186(EXCHG.65).aspx

Glad you managed to sort it out.
Thanks Terry. Regarding the Incremental backup, I guess this is much quicker than running a full backup and automatically purges the commited logs once the backup has run? Are there any disadvantages to this? I assume my normal, daily Full backups will still work and are unaffected?

Ok as incremental backups only backup the transaction logs, it will be much quicker as you only have to backup the transactions since your last full or incremental backup. The main disadvantage to this is when you restore you have to restore your full and all your incremental backups. Your normal full backups will not be effected as this is a full database backup, and does not require the transation logs. incremental backups are also good if you want to restore to a point in time.
Thanks Terry.

So I can take an incremental backup purely to clear the logs, then take a full backup in the evening as usual....the full backup (and any restore of it) would run as any other, regardless of the fact that the incremental had been run?

And is the point of the incremental purely to backup and purge commited logs? Is there no way in Exchange Management Console that it I can find out which logs have already been commited and move them elsewhere?
The transations are committed to the database fairly instantly.
 
The only way to safely move the log files is to use the move logs option in Exchange which dismounts the store moves the files then remounts. Do not manually move the files just because you know that are committed to the database as you will struggle to mount the database again if the database becomes dismounted.
as for the manual move, in my earlier post I linked to an article that had the best step by step guide of how to do it. If the management console had a nice clean way, it would have been shown there.

MS does not really want people poking about in the log files unnecessarily as this can be a cause of HUGE grief, so they have not included anything other than the move function in the EMC.
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