Exchange 2010 inetpub log files

We are running Exchange 2010 on MS Server 2008 R2.  We have our EDBs on drive E:\ and our ExchangeLogs on drive F:\.  Our nightly backups purge the logs and we keep both these drives with plenty of headroom.  Last night, however, our Exchange server reported severe backflow issues, and I eventually realized that the C:\ drive was 98% full.  This looks largely due to C:\inetpub, which is severely bloated, and doesn't seem to be getting purged by anything automatically.  More worrisome is that 10 days ago, each daily log file suddenly jumped from around 70 MB to 1 GB, in one day!  

1. Can someone shed some light on what these log files are and how they pertain to my Exchange server?
2. What are possible reasons for such a dramatic increase in size, as I can't recall any changes we've made in the last 10 days?
3. As a stopgap measure, to avoid my C:\ drive from filling up over night, can I manually delete old log files safely?
4. As a longterm solution, what is best practice for this directory?

Much thanks!
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The inetpub log files will be for logs associated with services such as the web server running on that box.  Do you run OWA on the same server?  It may be attempts to hack your server, it may be malfunctioning mobile clients.  It may be even that someone turned up diagnostic logging on that system.

I would copy over one or more of the 1GB log files and open with something other than notepad.  Word will probably handle it.   Look in the log and see what the errors are stating.

As to deleting these files, yes.  Generally the log files in this location are safe to delete, however without knowing what is going on you may determine it is best to keep them around in case you find there is an intrusion in your system.  I would advise buying an external drive and copying the log files there until you determine what is going on.

If you can post a few lines from the logs it would go a long way in helping us help you.

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cuiincAuthor Commented:
thanks.  we do run OWA on the same server, although we don't have many users (only a couple actually) that use OWA.  

i couldn't open the file with Word (too big) but Wordpad can barely handle it.  It's been loading for 15 minutes now, and I think I'm only a third of the way through the file, but the loglines all look to be very similar.  I've pasted some below.  
...41 is our mail server and ...42 is our archive server.  It looks to be some kind of comm between these two servers. I'm not sure what to make of this, however, especially as it references Mac OS X, and we only have a couple users who use Macs.  

2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive MacOutlook/ 200 0 0 15
2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive MacOutlook/ 200 0 0 15
2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive MacOutlook/ 200 0 0 15
2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive MacOutlook/ 200 0 0 15
2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive MacOutlook/ 200 0 0 15
2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive MacOutlook/ 200 0 0 0
2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive MacOutlook/ 200 0 0 15
2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive MacOutlook/ 200 0 0 15
Gareth GudgerCommented:
For files that large I recommend downloading Log Parser Studio from Microsoft. Its free. And it will get the job done.

Primarily for Exchange, LPS can also be used for IIS.

Bas is correct on all points. It is up to you whether you keep them. Unfortunately, there is no native truncation process for these logs. Although I know a quick Google search on IIS log cleanup will reveal some scripts you could schedule. You can turn them off in IIS if you wish as well.
Adam FarageEnterprise ArchCommented:
2014-10-09 05:36:32 POST /EWS/Exchange.asmx - 443 CUI\emailarchive

Thats Outlook for Mac, which utilizes EWS. The OS running that version of Outlook for Mac is OSX 10.6.2 :) The 200 code up there also means it successfully connected (as that is HTTP 200 - OK).

IIS logs file tend to grow, and depending on the amount of traffic your clients are generating it can be rapid. I use the following at work and then set it up as a scheduled task..
cuiincAuthor Commented:
Thank you all for the insights.  One follow-up question, as I dig deeper:  Yesterday I went into IIS, clicked on the top-level server (my mail server), clicked on "logging," and selected "Do not create new log files."  I clicked through all the child-level websites to ensure that they inherited this setting.  Additionally, I removed the most recent 900 MB log file.  immediately, i saw new, empty log file get created.  

And today I have a day-old, huge log file in inetpub.  Are there any other locations I should be checking, or might have overlooked?
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