BLOB cache for Sharepoint
Blob cache is used in Sharepoint that to
cache the Larger files.In the below Article I explained in very details About the Caches
http://expertsharepoint.blogspot.de/2013/10/to-tune-sharepoint-2010-for-better.html
BLOB Cache/Disk-based caching controls caching for binary
large objects (BLOBs) such as image, sound, video, and some static content
files like CSS. Disk-based caching is fast. It eliminates the need for database
round trips. BLOBs are retrieved from the database once and stored on the Web
client. Further requests are served from the cache and trimmed based on
security.
How to enable BLOB caching:
1.
BLOB Cache needs to be enabled from
Web.Config.
2.
Make sure that there is enough space in the
drive/server where blob cache is stored.
3.
It’s important to understand that BLOB cache
is per-machine. So make sure that the BLOB cache settings are consistent across
the whole farm. You don’t want one server with 1 GB of BLOB cache and another
server with 4 GB of BLOB cache. You might see strange and inconsistency in
performance if you don’t configure BLOB cache consistently.
4.
By default, the disk-based BLOB cache is off
and must be enabled on the front-end Web server.
5.
In order to enable BLOB cache, locate the
Web.Config for the web application and edit it.
6.
The recommended approach for making such
changes in Web.Config file is through a feature receiver or PowerShell by
making use of SharePoint’s SPWebConfigModification class.
In the Web.Config file, find the following line:
<BlobCache
location=""
path="\.(gif|jpg|jpeg|jpe|jfif|bmp|dib|tif|tiff|ico|png|wdp|hdp|css|js|asf|avi|flv|m4v|mov|mp3|mp4|mpeg|mpg|rm|rmvb|wma|wmv)$"
maxSize="10" enabled="false" />
In this line, change the location attribute to specify a
directory that has enough space to accommodate the cache size.
To add or remove file types from the list of file types to
be cached, for the path attribute, modify the regular expression to include or
remove the appropriate file extension. If you add file extensions, make sure to
separate each file type with a pipe (|), as shown in this line of code.
To change the size of the cache, type a new number for
maxSize. The size is expressed in gigabytes (GB), and 10 GB is the default. It
is recommended that you not set the cache size smaller than 10 GB. When you set
the cache size, make sure to specify a number large enough to provide a buffer
at least 20 percent bigger than the estimated size of the content that will be
stored in the cache.
To enable the BLOB
cache, change the enabled attribute, from "false" to "true".
<BlobCache location="E:\DATA\BlobCache" path="\.(gif|jpg|jpeg|jpe|jfif|bmp|dib|tif|tiff|themedbmp|themedcss|themedgif|themedjpg|themedpng|ico|png|wdp|hdp|css|js|asf|avi|flv|m4v|mov|mp3|mp4|mpeg|mpg|rm|rmvb|wma|wmv|ogg|ogv|oga|webm|xap)$" maxSize="1" enabled="true" />
After enabling
blob cache in web.config, do an IISRESET and browse to the /settings.aspx
first, instead of home page (Collaboration portal site).
When we browse
to the settings.aspx, it will create the following files change.bin, dump.bin and flushcount.bin (all the files will be
1KB in size).
Browse to the
home page now, it will create a folder PUBLISHINGIMAGES, all the images rendered
from the database will be stored here and the above bin files will also get
updated (we can see the difference in file size)
You can use an STSADM command to flush all BLOB caches associated
with a specified Web application on different Web front-end computers on the
farm:
stsadm –o setproperty –propertyname blobcacheflushcount
–propertyvalue 11 –url http://mywebapp::port