Subject: Wintel and I/O Issues Pls Read Below
Hello, This information should help. I have thousands of customers running Transactional Logging on Domino without Performance issues. Yes we do have other issues but if setup properly this should not be an issue.
MOST IMPORTANT INFO REGARDING PERFORMANCE:
Hardware considerations
Dedicated RAID1 Array ← Important or Perf Issues are expected.
It is absolutely essential to place the transaction log directory on a separate physical device devoted solely to transaction logging. Part of the performance improvement you will gain from transaction logging depends on having a separate disk, which allows fast writes to the transaction log files. Putting the transaction log on the same drive as other files — the operating system, the Domino executables, the Domino data, the OS pagefile, etc. — can result in a significant performance degradation even in comparison with an R4 server, since the server must read from and write to these files as well. This activity causes contention for the disk head — for example, the server might be reading information from a database while the logger tries to write a change to the transaction log. This can limit or remove the performance gains from transaction logging. Even in an environment with a storage area network (SAN), or an environment with a large physical drive logically addressed as multiple drives (for example, AS/400 or S/390 systems), it is still crucial that the logical transaction logging drive maps to a separate, dedicated physical drive. Each Domino server requires its own transaction log drive, including partitioned servers. The rule of thumb is “one log device per data directory, and one data directory per log device.”
Mirroring the log drive is also crucial, as losing a log drive or encountering a hardware failure risks losing log extents that may not have been backed up, and it also panics the server. RAID0 does not have a mirrored disk, making the log drive a single point of failure. RAID5 can offer mirroring, but has performance degradation due to extra write operations compared to a RAID1 log disk. Note that the media strategy for the transaction log disk is independent of the general server and Domino data strategy — a company could use RAID5 for the operating system and Domino data, but use a RAID1 disk array for the transaction log. Note also that in clustered environments, losing the log disk causes clients to fail over to a cluster member.
The disk size will depend on the logging style that you choose. With circular logging, the server uses a maximum of 4 GB of disk space. A typical mail server logs about 1 GB per day. You can determine how much data your organization is logging by using the transaction logging statistics provided by the Recovery Manager task (discussed later). Under circular logging, the recommendation is to use a 4 GB disk. Disk space is inexpensive and having the maximum space ensures that the server does not need to commit changes to disk under suboptimal conditions.
With archive logging, Domino uses all available space on the log disk (even if you set “Use all available space on log device” to No in the Server document). Archive logging depends on having a third-party backup utility to back up log extents and make them available for re-use. Domino re-uses extents when possible; if no re-usable extents are available, Domino creates a new extent. Therefore, disk sizing depends on how often an organization backs up its log extents. Typically, a 9 GB disk array will be more than sufficient to allow administrators to postpone backups until off hours. Backup products can allow you to specify that log extents should be backed up at a certain time (3:00 AM, for instance) unless the log disk is becoming full (for example, more than 70 percent full), in which case the utility should perform an immediate backup.
Other things to consider:
Notes.ini Parameters that should be added either with the Server Down or Using the Set Config Command:
These Parameters below can be added using the Set Config command on the Server Console to avoid Transactional Logging on Databases that should not be logged (Example SET CONFIG LOG_DISABLETXNLOGGING=1). The parameters will not take effect until the server is shutdown completely, the databases are removed and when the server is rebooted a new log.nsf, clubusy.nsf will be recreated and no longer be transactionally logged. All corresponding Technotes for these parameters are below the NSD Review: TN#1238392, TN#1251117, in versions prior to 8.5 we disabled Mail.box but that is no longer the case in 8.5
LOG_DisableTXNLogging=1 (Disabled TXN Logging on the Log.nsf)
Schedule_disabletxnlogging=1 (Disabled TXN Logging on the Clubusy.nsf)
You can also disable Transactional Logging for the following Databases on your server and the next time the server is restarted these databases will not be transactionally logged as it is unnecessary: names.nsf, statrep.nsf, statmail.nsf, webadmin.nsf, cldbdir.nsf. Note you do not have to recreate these database you just need to disable TXN Logging in the databases and the next time the server is restarted they will be excluded from the Logging.
To Turn Off Transactional Logging you can open the database and then go to File–>Database–>Properties–>Advanced tab
TECHNOTES:
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Title: Notes/Domino Best Practices: Transaction Logging
Doc #: 7009309
URL: http://www.ibm.com/support/docview.wss?rs=899&uid=swg27009309
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Title: Disabling transaction logging by default on log.nsf
Doc #: 1238392
URL: http://www.ibm.com/support/docview.wss?rs=899&uid=swg21238392
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Title: Transaction Log grows and fills hard drive
Doc #: 1251117
URL: http://www.ibm.com/support/docview.wss?rs=899&uid=swg21251117
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