Disk monitoring

Posted on 2011-10-30
Last Modified: 2013-12-06

I'm not too sure if I've chosen the correct zones, but this is in relation to disk IO and activites.

We have servers that are constantly writing/reading at 100% at disk level. We are not sure what is causing this, but this appears to be dropping our connection from the PCs.

We would like to know if there's a really good tool out there for disk monitoring/analysis so that we know what's causing this?

We used perfmon, but nothing tells us whats hammering the disks.

Please advise.

Question by:goraek
    LVL 14

    Expert Comment

    by:Ehab Salem
    If you have a RAID, there might be some rebuilds going on. You need to check the RAID status.
    Did you check your Virtual memory usage, if it is very high it will lead to the same.
    LVL 5

    Expert Comment

    Process Explorer by Sysinternals - now Microsoft - shows the top disk I/O user on a second by second basis in the usage history at top right of the user interface.

    In addition to the comments by ehabsalem, it's worth checking if there any large backups running currently on the servers? It's best to scehdule these when server usage is lower, e.g. overnight.

    LVL 2

    Accepted Solution

    We did a defrag on the server, and now its running fine.
    Not sure what has caused it, but the defrag seems to do the trick.

    However, is it recommended to defrag a VM?
    LVL 27

    Expert Comment

    This question has been classified as abandoned and is closed as part of the Cleanup Program. See the recommendation for more details.
    LVL 5

    Expert Comment

    Several people have contributed to this question. It seems wrong not to give some credit for the efforts of others who have given their time freely to try and resolve the issue.

    LVL 8

    Expert Comment

    Just to comment on one thing... per the question of defragging...

    NEver, ever, defrag a server until you have imaged it.  Never ever chkdsk a server until you have imaged it.
    Never ever presume to do anything on a server drive without backing up a totally restorable image.

    We had a guy faced with a little disk corruption on a TS one time, no big thing, it was running fine, he was just servicing some stuff, ran a check and saw the chkdsk report recommend fixing  ...and so he decided to run a simple chkdsk /f

    Seemed basic/simple/easy enough...
    ...suddenly he was seeing all these lines of code running up the screen -forever-. When he called in during this unending scenario we hjad him immidiately shut it down.
    Long story short, for some reason we could never figure out, a simple chkdsk began trashing the $mft and other $xxx (efs etc) and trashed files as well (we could tell all this on the on the audit of raw recovered image)... total fubar.

    Took all nite to restore this server... thank goodness we had everyone to work when doors opened in the morning.  


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