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Oplocks On cause issues opening multiple files over WAN


If you run into a situation where your Isilon is located in one city and you have a remote office with a Creative Services group in another city than this article is for you.

Because of the size of the adobe files that where being worked with and the limited 200MB pipe in between the 2 sites when a file copy over SMB 2 was initiated the Creative Services workstation basically locked up until that file transfer was done. This caused major headaches for the creative services crew as they where working with files that could be multiple gigs in size and during the transfers they were losing out on productivilty.

Now WAN Optimization would help as well one thing you can do on the Isilon in this situation is to run the following command to see if Oplocks are on.

isi smb settings share view

Sample outlook

MSPISIX400-1# isi smb settings share view

          Access Based Enumeration: No

Access Based Enumeration Root Only: No

             Allow Delete Readonly: No

              Allow Execute Always: No

                     Change Notify: all

                Create Permissions: default acl

             Directory Create Mask: 0700

             Directory Create Mode: 0000

                  File Create Mask: 0700

                  File Create Mode: 0100

                    Hide Dot Files: No

                          Host ACL: -

                 Impersonate Guest: always

                  Impersonate User:

                 Mangle Byte Start: 0XED00

                        Mangle Map: 0x01-0x1F:-1, 0x22:-1, 0x2A:-1, 0x3A:-1, 0x3C:-1, 0x3E:-1, 0x3F:-1, 0x5C:-1

                  Ntfs ACL Support: Yes

                           Oplocks: Yes

                      Strict Flush: Yes

                    Strict Locking: No

AS you can see the Oplocks are on. To turn them off run the following command

isi smb settings share modify –oplocks=no

(this will turn the oplocks off but you have to reconnect the SMB session for it to take effect.

After we flipped the oplocks off the Creative workstations could work on other files while the transfer was taken place unlike before when they couldn't do anything.

Hope this helps everyone out.

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