High disk activity on SBS 2008 and SBS 2011 is an ongoing concern for our clients. Just yesterday, we had an SBS 2011 server with so much disk activity that it slowed down the Hyper-V host so that all VMs were not performing properly.
To diagnose this issue, use Resource Monitor to view the Queue Length. When there is a problem the Queue length for a drive will be high and sustained. The % Active Time will also be high. These indicate that the disk is busy and has a backlog of work to perform.
It's important to note that the actual disk I/O may not be that high. In our case, the Disk I/O was less than 10 MBps which is far less than the disk system is capable of. The Disk I/O can be low but the disks busy when many small operations are performed.
The fix for this is almost always recreating the SBS Monitoring database. The SBS Monitoring database grows over time and eventually becomes a performance issue. We don't use any historical information in that database. So, removing it and recreating it is a good solution for us. It's a 10 minute fix that lasts for about a year before needing to be done again.
Microsoft instructions for how to recreate the SBS Monitoring database are here:
You can verify that the SBS Monitoring database is the issue by stopping theSQL Server (SBSMONITORING) service. After stopping that service, you should see disk activity slow down significantly.
On a physical host, the SBS Monitoring database will cause high Disk I/O on the C: drive. On a hyper-V host, the SBS Monitoring database will cause high Disk I/O on the physical drive that is hosting the C: drive VHD for SBS. Monitoring Disk I/O inside of a virtual machine will not be accurate.
Showing posts with label SBS. Show all posts
Showing posts with label SBS. Show all posts
Tuesday, March 3, 2015
Monday, October 17, 2011
SBS 2011 Exchange Not Installing
We have done several migrations from SBS 2003 to SBS 2011 without any significant incidents. This week we had a bit of hassle with Exchange 2010 not installing during the installation. No errors were reported by any of the premigration tools.
In the Exchangesetup.log and SBSSetup.log we got the following error:
At this point, we figured that maybe there was something weird because we had selected to download and install updates as part of the install. So, for attempt number two we did not install the updates and got a different error about being unable to find a domain controller. This one turns out to be an error that can occur if you have restored system state on Windows 2003. Apparently the file replication service gets confused. And although the KB for the hotfix below appears completely unrelated it seemed to resolve the issue. See the following:
Onward with further attempts and the original error continued. More searching and there were a fair number of references to registry keys specifying the restart was required, but we checked those and they did not exist on our server. However, for your reference:
We also found a few references to automatic printer installation causing this issue. This client does have a GPO that automatically installs printers. So, we disabled that and still no fix.
We think the problem was that DHCP was not configured on the source server. This client has an IP-based phone system that provides DHCP. This was configured by the phone provider to ensure that the necessary options are pushed out to the phones. When you configure the answer file for SBS 2011 installation there is a checkbox asking you to select whether DHCP is installed on the source server. However, the documentation explicitly states that DHCP must be installed and configured on the source server.
When DHCP was installed on the SBS 2003 server, it would not run because it conflicted with the DHCP on the phone system. So, finally, SBS 2003 and the new SBS 2011 were isolated off the main network. Then installation proceeded as normal.
Just for the record, my business partner Darrin is the one who finally figured this out.
In the Exchangesetup.log and SBSSetup.log we got the following error:
[REQUIRED] A reboot from a previous installation is pending. Please restart the system and rerun setup.Based on some quick research, the general recommendation seems to be that you should reinstall SBS 2011 rather than trying to add Exchange 2010 after the fact. So, to recover, we restored the system state to the old SBS 2003 server (which we cleverly created just before starting the installation).
At this point, we figured that maybe there was something weird because we had selected to download and install updates as part of the install. So, for attempt number two we did not install the updates and got a different error about being unable to find a domain controller. This one turns out to be an error that can occur if you have restored system state on Windows 2003. Apparently the file replication service gets confused. And although the KB for the hotfix below appears completely unrelated it seemed to resolve the issue. See the following:
Onward with further attempts and the original error continued. More searching and there were a fair number of references to registry keys specifying the restart was required, but we checked those and they did not exist on our server. However, for your reference:
We also found a few references to automatic printer installation causing this issue. This client does have a GPO that automatically installs printers. So, we disabled that and still no fix.
We think the problem was that DHCP was not configured on the source server. This client has an IP-based phone system that provides DHCP. This was configured by the phone provider to ensure that the necessary options are pushed out to the phones. When you configure the answer file for SBS 2011 installation there is a checkbox asking you to select whether DHCP is installed on the source server. However, the documentation explicitly states that DHCP must be installed and configured on the source server.
When DHCP was installed on the SBS 2003 server, it would not run because it conflicted with the DHCP on the phone system. So, finally, SBS 2003 and the new SBS 2011 were isolated off the main network. Then installation proceeded as normal.
Just for the record, my business partner Darrin is the one who finally figured this out.
Tuesday, August 16, 2011
SBS 2008 Monitoring Database Problems
I've run into performance issues on SBS 2008 servers related to the monitoring database. I've noticed this issue as a disk access issue when a server is slow. From Resource Monitor, sorting processes under Disk by the Read Bytes has the SBSMonitoring.mdf file with far more activity that other sources. Typically processor and memory utilization are OK, but not necessarily.
Two separate issues can be the source of the problem:
Two separate issues can be the source of the problem:
- SBS Monitoring database is too large and is using large amounts of disk space. If so, check this out: http://blog.korteksolutions.com/the-sbsmonitoring-database-is-nearing-maximum-size-on-sbs-2008/. I used the downloadable new database from this location and it worked great.
- Missing indexes in SBS Monitoring database cause high disk and maybe processor activity. If so, check this out: http://social.technet.microsoft.com/Forums/en/smallbusinessserver/thread/d195baac-da8b-4387-9079-c55d5e1879b4
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