Content database limits suggested by Microsoft in SharePoint 2013

The following table lists the recommended guidelines for content databases.

Limit
Maximum value
Limit type
Notes

Number of content databases
 500 per farm
  The maximum number of content databases per farm is 500. With 500 content databases per web application, end user operations such as opening the site or site collections are not affected. But administrative operations such as creating a new site collection will experience decrease in performance. We recommend that you use PowerShell to manage the web application when a large number of content databases are present, because the management interface might become slow and difficult to navigate.
 With 200GB per content database, and 500 content databases per farm, SharePoint Server 2013 supports 100TB of data per farm.

Content database size (general usage scenarios)
 200 GB per content database
  We strongly recommended limiting the size of content databases to 200 GB, except when the circumstances in the following rows in this table apply.
 If you are using Remote BLOB Storage (RBS), the total volume of remote BLOB storage and metadata in the content database must not exceed the 200GB limit.

Content database size (all usage scenarios)
 4 TB per content database
  Content databases of up to 4 TB are supported when the following requirements are met:
 Disk sub-system performance of 0.25 IOPS per GB. 0.2 IOPS per GB is recommended for optimal performance.
 You must have developed plans for high availability, disaster recovery, future capacity, and performance testing.
 You should also carefully consider the following factors:
 Requirements for backup and restore may not be met by the native SharePoint Server 2013 backup for content databases larger than 200 GB. It is recommended to evaluate and test SharePoint Server 2013 backup and alternative backup solutions to determine the best solution for your specific environment.
 It is strongly recommended to have proactive skilled administrator management of the SharePoint Server 2013 and SQL Server installations.
 The complexity of customizations and configurations on SharePoint Server 2013 may necessitate refactoring (or splitting) of data into multiple content databases. Seek advice from a skilled professional architect and perform testing to determine the optimum content database size for your implementation. Examples of complexity may include custom code deployments, use of more than 20 columns in property promotion, or features listed as not to be used in the over 4 TB section below.
 Refactoring of site collections allows for scale out of a SharePoint Server 2013 implementation across multiple content databases. This permits SharePoint Server 2013 implementations to scale indefinitely. This refactoring will be easier and faster when content databases are less than 200 GB.
 It is suggested that for ease of backup and restore that individual site collections within a content database be limited to 100 GB. For more information, see Site collection limits.
 
IMPORTANT We do not recommend the use of content databases that exceed 4 TB, except in document archive scenarios (described in the next row in this table). If, in the future, you need to upgrade your SharePoint Server 2013 installation, upgrading the site collections within the content databases can be very difficult and time consuming. > It is strongly recommended that you scale out across multiple content databases, rather than exceed 4 TB of data in a single content database.

Content database size (document archive scenario)
 No explicit content database limit
 Supported
 Content databases with no explicit size limit for use in document archive scenarios are supported when the following requirements are met:
 You must meet all requirements from the "Content database size (all usage scenarios)" limit earlier in this table, and you should ensure that you have carefully considered all the factors discussed in the Notes field of that limit.
 SharePoint Server 2013 sites must be based on Document Center or Records Center site templates.
 Less than 5% of the content in the content database is accessed each month on average, and less than 1% of content is modified or written each month on average.
 Do not use alerts, workflows, link fix-ups, or item level security on any SharePoint Server 2013 objects in the content database.
Note: Document archive content databases can be configured to accept documents from Content Routing workflows.
 For more information about large-scale document repositories, see Estimate performance and capacity requirements for large scale document repositories in SharePoint Server 2010, and the Typical large-scale content management scenarios section of the article Enterprise content storage planning (SharePoint Server 2010).

Content database items
 60 million items including documents and list items
 Supported
 The largest number of items per content database that has been tested on SharePoint Server 2013 is 60 million items, including documents and list items. If you plan to store more than 60 million items in SharePoint Server 2013, you must deploy multiple content databases.

Site collections per content database
 10,000 maximum (2,500 non-Personal site collections and 7,500 Personal Sites, or 10,000 Personal Sites alone)
 Supported
 We strongly recommended limiting the number of site collections in a content database to 5,000. However, up to 10,000 site collections in a database are supported. Note that in a content database with up to 10,000 total site collections, a maximum of 2,500 of these can be non-Personal site collections. It is possible to support 10,000 Personal site collections if they are the only site collections within the content database.
 These limits relate to speed of upgrade. The larger the number of site collections in a database, the slower the upgrade with respect to both database upgrade and site collection upgrades.
 The limit on the number of site collections in a database is subordinate to the limit on the size of a content database that has more than one site collection. Therefore, as the number of site collections in a database increases, the average size of the site collections it contains must decrease.
 Exceeding the 5,000 site collection limit puts you at risk of longer downtimes during upgrades. If you plan to exceed 5,000 site collections, we recommend that you have a clear upgrade strategy to address outage length and operations impact, and obtain additional hardware to speed up the software updates and upgrades that affect databases.
 To set the warning and maximum levels for the number of sites in a content database, use the PowerShell cmdlet Set-SPContentDatabase with the -WarningSiteCount parameter. For more information, see Set-SPContentDatabase.

Remote BLOB Storage (RBS) storage subsystem on Network Attached Storage (NAS)
 Time to first byte of any response from the NAS should remain within 40 milliseconds 95% of the time.
 Boundary
 When SharePoint Server 2013 is configured to use RBS, and the BLOBs reside on NAS storage, consider the following supported limit.
 From the time that SharePoint Server 2013 requests a BLOB, until it receives the first byte from the NAS, 95% of the time no more than 40 milliseconds can pass.

Reference :  https://docs.microsoft.com/en-us/sharepoint/install/software-boundaries-and-limits

 

Recover data from an unattached content database - Sharepoint 2010

Wow One more amazing feature .

Now you can Recover data from an unattached content database . you dont have to add the content database to a web application

As a Sharepoint administrator there might be a need to restore only some but not all content within a content database. How would you do that in SharePoint 2010 .

In earlier versions of SharePoint, to restore or recover content from a backup file, we had to restore the backed up file to a database server and had to attach that restored database to a another SharePoint farm. Then we needed to export the required content from this new temporary farm and then migrate it to the original farm where we wanted to recover it. This whole process required a huge time investment and rigorous planning.

To recover content from an unattached content database by using Central Administration

* Verify that the user account that is performing this procedure is a member of the Farm Administrators group and is a member of the db_owner fixed database role.

* In Central Administration, on the Home page, click Backup and Restore.

* On the Backup and Restore page, in the Granular Backup section, click Recover data from an unattached content database.

* On the Unattached Content Database Data Recovery page, type the database server name in the       
    Database Server text box and type the database name in the Database Name text box.

* Select the database authentication method that you want to use.

* Select the Browse content option, and then click Next.

* Click Start Restore.

* On the Browse content page, select the site collection, site, and or list that you want to restore, select the
   Backup site collection or Export site or list option, and then click Next.

Complete the process to restore the content.

To recover content from an unattached content database by using Windows PowerShell

Verify that you meet the following minimum requirements: See Add-SPShellAdmin.

On the Start menu, click All Programs.
Click Microsoft SharePoint 2010 Products.
Click SharePoint 2010 Management Shell.
At the Windows PowerShell command prompt, type the following command

Get-SPContentDatabase -ConnectAsUnattachedDatabase  -DatabaseName <DatabaseName> -DatabaseServer <DatabaseServer>

Where:
<DatabaseName> is the name of the unattached database from which you want to recover content.
<DatabaseServer> is the name of the database server that hosts the unattached database from which you want to recover content

For reference - http://technet.microsoft.com/en-us/library/hh269601(v=office.14).aspx

Capacity Management - Content database limits

Limit	Maximum value	Limit type	Notes
Content database size (general usage scenarios)	200 GB per content database	Supported	We strongly recommended limiting the size of content databases to 200 GB, except when the circumstances in the following rows in this table apply. If you are using Remote BLOB Storage (RBS), the total volume of remote BLOB storage and metadata in the content database must not exceed this limit.
Content database size (all usage scenarios)	4 TB per content database	Supported	Content databases of up to 4 TB are supported when the following requirements are met: Disk sub-system performance of 0.25 IOPs per GB. 2 IIOPs per GB is recommended for optimal performance. You must have developed plans for high availability, disaster recovery, future capacity, and performance testing. You should also carefully consider the following factors: Requirements for backup and restore may not be met by the native SharePoint Server 2010 backup for content databases larger than 200 GB. It is recommended to evaluate and test SharePoint Server 2010 backup and alternative backup solutions to determine the best solution for your specific environment. It is strongly recommended to have proactive skilled administrator management of the SharePoint Server 2010 and SQL Server installations. The complexity of customizations and configurations on SharePoint Server 2010 may necessitate refactoring (or splitting) of data into multiple content databases. Seek advice from a skilled professional architect and perform testing to determine the optimum content database size for your implementation. Examples of complexity may include custom code deployments, use of more than 20 columns in property promotion, or features listed as not to be used in the over 4 TB section below. Refactoring of site collections allows for scale out of a SharePoint Server 2010 implementation across multiple content databases. This permits SharePoint Server 2010 implementations to scale indefinitely. This refactoring will be easier and faster when content databases are less than 200 GB. It is suggested that for ease of backup and restore that individual site collections within a content database be limited to 100 GB. Important: Content databases of over 4 TB, except for use in document archive scenarios (described in the row below), are not recommended. Upgrading of site collections within these content databases is likely to be very difficult and time consuming. It is strongly recommended that you scale out across multiple content databases, rather than exceed 4 TB of data in a single content database.
Content database size (document archive scenario)	No explicit content database limit	Supported	Content databases with no explicit size limit for use in document archive scenarios are supported when the following requirements are met: You must meet all requirements from the “Content database size (all usage scenarios)” limit earlier in this table, and you should ensure that you have carefully considered all the factors discussed in the Notes field of that limit. SharePoint Server 2010 sites must be based on Document Center or Records Center site templates. Less than 5% of the content in the content database is accessed each month on average, and less than 1% of content is modified or written each month on average. Do not use alerts, workflows, link fix-ups, or item level security on any SharePoint Server 2010 objects in the content database. Note: Document archive content databases can be configured to accept documents from Content Routing workflows.
Content database items	60 million items including documents and list items	Supported	The largest number of items per content database that has been tested on SharePoint Server 2010 is 60 million items, including documents and list items. If you plan to store more than 60 million items in SharePoint Server 2010, you must deploy multiple content databases.
Site collections per content database	2,000 recommended 5,000 maximum	Supported	We strongly recommended limiting the number of site collections in a content database to 2,000. However, up to 5,000 site collections in a database are supported. These limits relate to speed of upgrade. The larger the number of site collections in a database, the slower the upgrade. The limit on the number of site collections in a database is subordinate to the limit on the size of a content database that has more than one site collection (200 GB). Therefore, as the number of site collections in a database increases, the average size of the site collections it contains must decrease. Exceeding the 2,000 site collection limit puts you at risk of longer downtimes during upgrades. If you plan to exceed 2,000 site collections, we recommend that you have a clear upgrade strategy, and obtain additional hardware to speed up upgrades and software updates that affect databases. To set the warning level for the number of sites in a content database, use the Windows PowerShell cmdlet Set-SPContentDatabase with the -WarningSiteCount parameter.
Remote BLOB Storage (RBS) storage subsystem on Network Attached Storage (NAS)	Time to first byte of any response from the NAS cannot exceed 20 milliseconds	Boundary	When SharePoint Server 2010 is configured to use RBS, and the BLOBs reside on NAS storage, consider the following boundary. From the time that SharePoint Server 2010 requests a BLOB, until it receives the first byte from the NAS, no more than 20 milliseconds can pass.