Before you Upgrade to SQL 2012 where SharePoint databases reside.

Please make sure to go through these articles before you upgrade to SQL 2012 where SharePoint databases are hosted.

SQL server 2012 is supported and works with SharePoint 2010 only if the SharePoint environment is on SP1 or higher
http://msdn.microsoft.com/en-us/library/hh231665(v=sql.110).aspx

Upgrade to SQL Server 2012

http://msdn.microsoft.com/en-us/library/bb677622.aspx

Supported Version and Edition Upgrades

http://msdn.microsoft.com/en-us/library/ms143393.aspx

Upgrade PowerPivot for SharePoint

http://msdn.microsoft.com/en-us/library/ee210646(SQL.110).aspx

Upgrade and Migrate Reporting Services

http://msdn.microsoft.com/en-us/library/ms143747.aspx 

Upgrade Analysis Services

http://msdn.microsoft.com/en-us/library/ms143686.aspx

Site Slowness due to Certificate CRL Checking.

Issue:- You can have ADFS sites or Kerberos or basic configuration sites using hardware appliances for NLB e.g. F5 or Big IP or you can also be using SiteMinder. You may experience slowness while loading the site.

Troubleshooting:-

If you collect Fiddler trace you will see CRL checking to Microsoft site.

   

GET http://crl.microsoft.com/pki/crl/products/CSPCA.crl

GET http://crl.microsoft.com/pki/crl/products/microsoftrootcert.crl

Resolution:-

1. Disabled Certification Revocation checking.

http://support.microsoft.com/kb/2625048

OR

1. netsh http show sslcert (* check if 'Verify Client Certificate Revocation : Enabled' *)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters\SslBindingInfo\0.0.0.0:443 -> DefaultSslCertCheckMode = 1

2. reboot server

3. netsh http show sslcert (* check if 'Verify Client Certificate Revocation : Disabled' *)

Consideration to Improve Performance for SharePoint 2010 Servers.

Performance of SharePoint 2010 Servers.

Performance is always a big topic of Discussion in Any Organization. No matter how much CPU or RAM you add to the Servers, most of the time Users will complain that the sites are slow, or sudden fluctuations in CPU going consistently high, or Customization issues, SQL Deadlock errors etc... etc.. the list goes on.

Here are some of the very Important things to look at Configuration settings and Troubleshoot certain things, which you may face in various different SharePoint Environments.

Many of the known performance issues like UPA sync is slow from Active Directory or Search crawling has suddenly become slow can be caused due to some SQL or OS related configurations not done correctly or they are not in place at all.

Here are some of the STRONGLY recommended articles that should be followed.

SQL Maxdop setting should NOT be 0
========================================
http://technet.microsoft.com/en-us/library/hh292622.aspx
Set max degree of parallelism (MAXDOP) to 1 for SQL Server instances that host SharePoint Server 2010 databases to ensure that each request is served by a single SQL Server process

Anti-Virus check.
====================
Certain folders may have to be excluded from antivirus scanning when you use a file-level antivirus program in SharePoint
http://support.microsoft.com/kb/952167

SQL TempDB configuration and Optimization.
===================================================
http://msdn.microsoft.com/en-us/library/ms175527.aspx
http://blogs.msdn.com/b/joaquint/archive/2011/02/08/sharepoint-and-the-importance-of-tempdb.aspx

Database maintenance for SharePoint 2010 Products
http://technet.microsoft.com/en-us/library/cc262731.aspx

Disable Certification Revocation checking.
http://support.microsoft.com/kb/2625048

SQL Deadlock errors. Event ID 10016 in logs.
We need to disable following settings on ALL the SharePoint Servers and also SQL Servers. If SQL Server is in Cluster, all the nodes in the cluster also needs to be changed. After making the Changes, Reboot of all the Servers including SQL servers is Mandatory.

1. TCP Chimney Offload http://support.microsoft.com/kb/951037. by Default in Wind 2008 Servers, this setting is "Automatic", we need to Disable it. "netsh int tcp set global chimney=disabled"

2. IP Task Offload. by Default in Wind 2008 Servers, this setting is "Enabled", we need to disable it. "netsh int ip set global taskoffload=disabled". This is also applicable for Fast for SharePoint Server issues. http://support.microsoft.com/kb/2570111

3. NIC settings should be Disabled.

IPv4 Checksum Offload”, “Large Send Offload” and “TCP Checksum offload” [ note: this may require a hard reboot of the servers ]

Why to Disable TCP Chimney on SQL Servers?
http://blogs.msdn.com/b/psssql/archive/2008/10/01/windows-scalable-networking-pack-possible-performance-and-concurrency-impacts-to-sql-server-workloads.aspx

Other Tool you are use to Troubleshoot.

Use Developer Dashboard.
==================================
http://blogs.technet.com/b/patrick_heyde/archive/2009/11/16/sharepoint-2010-enable-using-developer-dashboard.aspx
stsadm -o setproperty -pn developer-dashboard -pv ondemand

SharePoint 2010 Search Query component is not responding. Synchronizing state.

Issue:- Search Topology has multiple Query components and after some Server reboots or patch updates or network connectivity issues, we get below error in the Logs.

Error:-

The following conditions are currently affecting index propagation to this server for search service application 'Enterprise Search':   1. Query 3, catalog Main: failing to copy index files from crawl component 2 for 105737 minutes. The network path was not found.   0x80070035  2. Query 3 is not being automatically disabled because the minimum number of ready query components per partition is 2.
01-14-2012 12:00:12.48 OWSTIMER.EXE (0x0958) 0x09B8 SharePoint Server Search Administration f6ql Warning The following conditions are currently affecting index propagation to this server for search service application 'Partitioned Search':   1. Query 1, catalog Main: failing to copy index files from crawl component 1 for 105658 minutes. The network path was not found.   0x80070035  2. Query 1 is not being automatically disabled because the minimum number of ready query components per partition is 2. d39bcb4a-a193-427f-9fcc-f65cd6127a73

01-14-2012 12:10:02.04 OWSTIMER.EXE (0x0958) 0x09CC SharePoint Foundation Topology 8xqz Medium Updating SPPersistedObject SearchQueryAndSiteSettingsServiceInstance. Version: 1489237 Ensure: False, HashCode: 22838785, Id: 4bfc05dd-9ba0-40f0-be26-427f7e05a614, Stack:    at Microsoft.SharePoint.Administration.SPPersistedObject.BaseUpdate()     at Microsoft.SharePoint.Administration.SPIisWebServiceInstance.Unprovision()     at Microsoft.SharePoint.Administration.SPServiceInstanceJobDefinition.Execute(Guid targetInstanceId)     at Microsoft.SharePoint.Administration.SPAdministrationServiceJobDefinition.ExecuteAdminJob(Guid targetInstanceId)     at Microsoft.SharePoint.Administration.SPTimerJobInvokeInternal.Invoke(SPJobDefinition jd, Guid targetInstanceId, Boolean isTimerService, Int32& result)     at Microsoft.SharePoint.Administration.SPTimerJobInvoke.Invoke(TimerJobExecuteData& data, Int32& result) 3860aa69-0248-463f-879e-cc473cddfba1

Resolution:-
You will have to create new Query Components and delete the Old ones following below article.

Search query critical error - Event 60 (SharePoint Server 2010)
http://technet.microsoft.com/en-us/library/ee513123.aspx

Timer Service keeps Crashing / causes UPA Sync to stop working.

Issue:- UPA Sync Service will stop functioning intermitently. During troubleshooting, you may not find any errors or Event's logged for this. You may also notice that the Timer Service is crashing every 2-3 mins if you keep an eye on the Services console.

Troubleshooting:- You can use Microsoft Procmon Tool to check if any Service is causing it crash or what might be interrupting the UPA and Timer Services to function properly.

Resolution:- Anti-Virus software is the main cause for such issues. Once you exclude SharePoint folders following the below article you need to restart/re-provision UPA and UPA Sync Service from Central Administration page.

Certain folders may have to be excluded from antivirus scanning when you use a file-level antivirus program in SharePoint
http://support.microsoft.com/kb/952167 

New AD Users not getting resolved in People Picker

Issue:- Any New User or Group created in Active Directory is not getting resolved in a specific SharePoint Site collection People Picker. It works fine for other Web Applications and if you create a new Site Collection in the same Web app, People Picker is resolving new Users and Groups there.

For the problematic Site Collection, the old Existing User accounts and Groups are resolving fine, only the New ones are not getting resolved in People Picker.

Resolution:-

Get-SPSite "http://SharePoint/sites/collection" | fl > C:\props.txt 

If you open the Props.txt file, you will see the properties for this site collection. Look for "UserAccountDirectoryPath" property. By Default it should be blank, if it is not, that is causing new Users in AD not to be resolved in People Picker.

To Change the Property value to Blank, follow as below.

$Site = Get-SPSite "http://SharePoint/sites/collection"

$Val=""

$Site.UserAccountDirectoryPath = $val

Note:- You can also first troubleshoot by creating a new Site collection in Same Web app and check if the issue is similar as per this blog.

SP 2010 User Profile Sync Service Won't start

Issue: SharePoint 2010 User Profile Sync Service won't start. As many are already pulling their hair over the UPA Sync service issues, one of the errors and resolution is as below.

Error:-

02/22/2012 11:49:18.87 OWSTIMER.EXE (0x1A10) 0x0AE8 SharePoint Portal Server User Profiles g4wt High UpdateILMMA: Failed to update password. Exception: {1}.. Available parameters: Microsoft.ResourceManagement.WebServices.Client.PermissionDeniedException: Access to the requested resource(s) is denied at Microsoft.ResourceManagement.WebServices.Client.ResourceTemplate.GetResource(UniqueIdentifier identifier, String[] attributeNames, Nullable`1 resourceTime) at Microsoft.ResourceManagement.WebServices.ResourceManager..ctor(UniqueIdentifier resourceIdentifier, String typeName, String[] attributeNames, CultureInfo locale, Boolean includePermissionHints, TimeZoneInfo localTimeZone) at Microsoft.ResourceManagement.WebServices.ResourceManager..ctor(UniqueIdentifier resourceIdentifier, String typeName, String[] attributeNames, CultureInfo locale, Boolean includePermissionHints) at Microsoft.Office.Server.UserProfiles.Synchronization.MAConfiguration..ctor(Guid resourceIdentifier) at Microsoft.Office.Server.UserProfiles.Synchronization.ILMMAConfiguration..ctor(Guid resourceIdentifier) at Microsoft.Office.Server.UserProfiles.UserProfileConfigManager.UpdateILMMA(String databaseServerIlm, String databaseInstanceIlm, String databaseName, String domain, String userName, SecureString password) . a4398ace-cf1f-4a23-a976-830806ce4c67

02/22/2012 11:49:18.87 OWSTIMER.EXE (0x1A10) 0x0AE8 SharePoint Portal Server User Profiles 9q17 High UserProfileApplication.SynchronizeMIIS: Failed to configure ILM MA, will attempt during next rerun. Exception: Microsoft.ResourceManagement.WebServices.Client.PermissionDeniedException: Access to the requested resource(s) is denied at Microsoft.ResourceManagement.WebServices.Client.ResourceTemplate.GetResource(UniqueIdentifier identifier, String[] attributeNames, Nullable`1 resourceTime) at Microsoft.ResourceManagement.WebServices.ResourceManager..ctor(UniqueIdentifier resourceIdentifier, String typeName, String[] attributeNames, CultureInfo locale, Boolean includePermissionHints, TimeZoneInfo localTimeZone) at Microsoft.ResourceManagement.WebServices.ResourceManager..ctor(UniqueIdentifier resourceIdentifier, String typeName, String[] attributeNames, CultureInfo locale, Boolean includePermissionHints) at Microsoft.Office.Server.UserProfiles.Synchronization.MAConfiguration..ctor(Guid resourceIdentifier) at Microsoft.Office.Server.UserProfiles.Synchronization.ILMMAConfiguration..ctor(Guid resourceIdentifier) at Microsoft.Office.Server.UserProfiles.UserProfileConfigManager.UpdateILMMA(String databaseServerIlm, String databaseInstanceIlm, String databaseName, String domain, String userName, SecureString password) at Microsoft.Office.Server.Administration.UserProfileApplication.SetupSynchronizationService(ProfileSynchronizationServiceInstance profileSyncInstance). a4398ace-cf1f-4a23-a976-830806ce4c67

02/22/2012 11:49:18.87 OWSTIMER.EXE (0x1A10) 0x0AE8 SharePoint Portal Server User Profiles 9i1u Medium UserProfileApplication.SynchronizeMIIS: End setup for 'UserProfileServiceApplication'. a4398ace-cf1f-4a23-a976-830806ce4c67

Log Name: Application

Source: FIMSynchronizationService
Date: 2/22/2012 11:49:18 AM
Event ID: 6331
Task Category: MA Extension
Level: Error
Keywords: Classic
User: N/A
Computer: computer.domain.com
Description:

A update on the configuration of a MA or MV failed to replicate to a target connector directory that is capable of storing MA/MV configurations. As a result, the MA/MV configuration data in this connector directory is not up to date. Please correct the condition that causes the error, and triggers a resync by updating the password information of the target MA.

Additional information:

Error Code: 0x80231317
Error Message: (The management agent failed to validate against the application store with the specified credentials.)
Operation: Clean up MAs
Name of the MA to replicate:
Name of the target MA: ILMMA
Guid of the target MA: {F2CD610F-9L7E1-45S2-834J-D76734328DFCAC4}

(The management agent failed to validate against the application store with the specified credentials.)

Clean up MAs


Resolution:-
1. Make sure you are logged into the Server as the UPA Service account.
2. Run RSOP information for account specifically for 'Allow Logon Locally' and 'Deny Logon Locally' GPO.
3. If the User Account is part of any AD group and that Group is added to the "Deny Logon Locally" policy, the UPA Sync service will NOT start.
4. The Service account has to be specifically be part of the "Allow Logon Locally" GPO.

PDF iFilter - Error "The file Exists"

Issue:- While crawling .pdf documents, some documents are crawled successfully and some are not. This can happen for either Adobe PDF iFilter or FoxIt PDF iFilter.

Error:- "The file Exists. (Exception from HRESULT: 0x80070050)".

Resolution:-
In case you are using Adobe PDF iFilter, follow below steps.

1.  Change the Registry key for ‘Default’ under \\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\14.0\Search\Setup\ContentIndexCommon\Filters\Extension to “{E8978DA6-047F-4E3D-9C78-CDBE46041603}”
a.  Perform net stop osearch14
b.  Net start osearch14
In case you are using FoxIt PDF iFilter, Follow below steps.

1. Change the Registry key for ‘Default’ under \\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\14.0\Search\Setup\ContentIndexCommon\Filters\Extension to“{987f8d1a-26e6-4554-b007-6b20e2680632}”,
a. Perform net stop osearch14
b. Net start osearch14