Karon, I'm about as stupid as they come when it comes to Exchange, but I fail to understand why you're having such a problem understanding this. Here is an excerpt for you to read. If after reading this, you still can't understand everyone's arguments for turning off circular logging, you may want to rething your career choice. ================================================= Excerpt from "Managing Microsoft Exchange Server" by Paul Robichaux, published by O'Reilly Books, printed in July 1999 and reprinted in May 2001.
Circular Logging - Chapter 2: Exchange Architecture, Pages 35-37 Since a new log file is created whenever the current one fills up, log files can potentially take up a large amount of space on your disk. One solution is to put them on a dedicated disk (more on that in Chapter 3, Exchange Planning); another is to enable circular logging. Normally, every log file is kept until its transactions have been committed; the files are usually purged when backups are made. However, when you enable circular logging, Exchange will keep a fixed number of log files, rolling from one to another as transactions arrive. The default number is four, but Exchange may use extra log files if a large set of transactions arrives. As the fourth log file fills up, Exchange will commit transactions from the first file; when the fourth file is completely full, all transactions will be flushed from the first file and it will be reused. However, since these additional log files are never deleted, a very busy server can still use more than the default 25MB circular logging allocation. Circular logging is turned on by default in Exchange. This is actually a bad thing, since with circular logging on, you only have the most recent transactions in the log files-older data is lost as the circle rolls around. Without a complete record of all transactions posted to the database, recovering the entire database may be difficult if you don't notice that it has been corrupted or damaged for a while. Circular logging also limits your backup choices, as you'll see in the next section. In Microsoft's defense,circular logging does keep log files from filling the entire disk, making it possible for novice administrators to run Exchange without being aware of its disk space or backup needs. Having said that, you should immediately turn circular logging off as soon as you install Exchange. When it's on, it's much more difficult to recover the IS from a backup. With 10GB disks selling for less than US$150, there's no excuse for not having enough disk space for the log files. Logging and the Databases - Chapter 17: Recovery and Repair, Page 555 The biggest stumbling block to successful Exchange recovery is circular logging; when you enable it, you're giving Exchange permission to throw away log data. With circular logging off, as long as you have a good copy of your transaction logs, you can restore your database to a consistent and correct state. If being able to recover your data is more important than the cost of having to buy enough disk space, turn circular logging off on your IS servers. ================================ -----Original Message----- From: Karon Miller [mailto:[EMAIL PROTECTED]] Sent: Thursday, August 08, 2002 1:09 PM To: Exchange Discussions Subject: RE: Backing up Exchange 5.5 I don't get it. What gives you the impression I don't know what Circular Logging is? Just because I have it turned on. I would turn it off if we could figure out how to back up the edb files and could flush the log files. It sounds like you don't really know what circular logging is, or what the > impact is. > > Please, for the sake of your job, your company and your company's mail > resources, locate and print out the Exchange 5.5 Backup and Disaster > Recovery whitepapers from MS' website. > > Do not leave the building without having the printouts in your hands. > > Do not go to sleep tonight until you have read them. All will be > explained in those whitepapers. > > > > > -----Original Message----- > > From: Karon Miller [mailto:[EMAIL PROTECTED]] > > Sent: Thursday, August 08, 2002 2:39 PM > > To: Exchange Discussions > > Subject: RE: Backing up Exchange 5.5 > > > > > > I know what circular logging is and that's why we have it > > turned on. > > > > My plan is to just stop the services and backup the pub.edb > > and priv.edb > > until we can get the OF Agent working. As far as BLB's, the > > FIRM has to > > do those I've tried to get them to not do them but they want > > to be able to > > restore a mailbox. This is a law firm remember the Lawyers > > are in charge > > not IT. > > > > Flushing the log files are I guess removing them or renaming them. > > > > > > Do you know what circular logging is? Do you know what the > > logfiles are > > > for? > > > > > > > > > > > > -----Original Message----- > > > From: Karon Miller [mailto:[EMAIL PROTECTED]] > > > Sent: Thursday, August 08, 2002 1:30 PM > > > To: Exchange Discussions > > > Subject: RE: Backing up Exchange 5.5 > > > > > > > > > On this particular server we are doing circular logging but > > that shouldn't > > > hurt anything. We were using BE's OFO but my Sys MGR again > > made us shut > > > it off because we were having constant problems with it. > > > > > > When you say flush the logs does, what exactly do you mean? > > > > > > > > > > > > OH MY GODS AND GODDESSES!! No wonder you have trouble with > > this server. > > > > Stop the BLB and do it the right way - pub and priv and > > flush logs when > > > > complete. You aren't doing circular logging too, are you? > > > > > > > > Just use the exchange agent from BE and you never have to stop > > > > ANY > > > service. > > > > > > > > -----Original Message----- > > > > From: Karon Miller [mailto:[EMAIL PROTECTED]] > > > > Sent: Thursday, August 08, 2002 1:20 PM > > > > To: Exchange Discussions > > > > Subject: Backing up Exchange 5.5 > > > > > > > > > > > > I know this has come up before but how is everyone else > > backing up their > > > > Exchange servers. We're using Backup Exec and only backing up > > > > the mailboxes not the pub.edb or priv.edb. Is it wise to > > stop those services > > > > periodically to back those up? And how often? We're not > > using the Open > > > > File Agent. > > > > > > > > _________________________________________________________________ > > > > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > > > > Archives: http://www.swynk.com/sitesearch/search.asp > > > > To unsubscribe: mailto:[EMAIL PROTECTED] > > > > Exchange List admin: [EMAIL PROTECTED] > > > > > > _________________________________________________________________ > > > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > > > Archives: http://www.swynk.com/sitesearch/search.asp > > > To unsubscribe: mailto:[EMAIL PROTECTED] > > > Exchange List admin: [EMAIL PROTECTED] > > > > _________________________________________________________________ > > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > > Archives: http://www.swynk.com/sitesearch/search.asp > > To unsubscribe: mailto:[EMAIL PROTECTED] > > Exchange List admin: [EMAIL PROTECTED] > > _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED]
