Unlike the fracture log, the WIL is active at all times and not just when the mirror is fractured.  During normal operation the WIL tracks every write to both the primary and secondary images and records this in a bitmap.  This bitmap is updated when a write I/O arrives for the source LUN and this entry is cleared after the data is written to both the Primary and Secondary LUNs (although this write will initially only be to write cache on both CLARiiON arrays if write cache is enabled).  Therefore, the performance demands on the WIL are proportional to the write I/O for synchronously mirrored LUNs on that SP. The Write Intent Log best practice is as follows:     [IMAGE]
Are there any issues with placing the Write Intent Log LUN's on Vault Drives, these are the only LUN's that will be located on thse disks?
Write Intent Log LUN's on Vault Drives