Site Collection Locks in SharePoint 2010

Some time back, I ran into a issue where a particular site collection was in read-only mode to every one including site collection admin, certain options such as site action menus were in disabled state!. Then I realized site collection backup process was interrupted due to disk-space issue and it left the site collection in "Read-only" mode! which was documented in my post SharePoint site is read-only to everyone

Screenshot from Read-only locked Site collection: Note that ribbon items are disabled!

Screenshot from Unlocked site:

SharePoint 2010 Locks can be Set/Reset in 4 ways:

1. Using Web User Interface - Through Central Administration
2. Using STSADM 
3. Using PowerShell
4. Using Object Model
1. By .Net code
2. By PowerShell

Lets Look at the examples:

Using Web User Interface:
Where to Look? Go to Central Administration > Application Management > Configure Quotas and Locks

 Under Site Collection Quotas and locks, set the site collection to "Not locked" will release the site.

STSADM:
To lock site collection:
stsadm -o setsitelock -url <Site-collection-url> -lock <Lock-Type>

To get site lock status information of SharePoint site collection:
stsadm -o getsitelock -url <Site-collection-url>

Where <Lock-Type> can take one of the following value:

• none  - Removes all the locks
• noadditions  - Prevents from Addition
• readonly - Can't add/Update/Delete content
• noaccess - You can't view the site at all

More info: http://technet.microsoft.com/en-us/library/cc262811.aspx

PowerShell to Set Site collection Lock:
Set-SPSite -Identity <Site-collection-url> -LockState <Lock-State>

Where: <Lock-State> can be:

•     ReadOnly
•     Unlock
•     NoAdditions
•     NoAccess 

More Info: http://technet.microsoft.com/en-us/library/cc263238.aspx

SharePoint Site Collection Locks Programmatically with Object Model:
You can Programmatically set the Lock status using SPSite object's Properties:

•     SPSite.ReadLocked
•     SPSite.WriteLocked
•     SPSite.ReadOnly

E.g:
using (SPSite site = new SPSite("http://sharepoint.com/sites/sales"))
            {            
                site.ReadOnly = true;
                //Set lock comments
                site.LockIssue = "Maintenance";
            }

PowerShell To Handle SharePoint Site Collection Locks:

$SPSite = Get-SPSite -Identity http://SharePoint

#Check whether the site collection is read-only

$SPSite.readonly

#Remove the site collection's read-only lock

$SPSite.readonly = $false

BTW, SharePoint Site collections may be locked automatically, when they exceeds the Site collection Quota!

Backup LIVE Site collection with out Locks:  
STSADM:   stsadm -o backup -url <Site-collection-url> -filename <Backup-File> -nositelock
PowerShell: Backup-SPSite -Identity <Site-collection-url> -Path <Backup-File> -NoSiteLock

PowerShell Script to check lock Status of All site collections: http://salaudeen.blogspot.com/2012/12/check-lock-status-for-all-site.html