Typically the first extent is the smallest power of 2 that is larger than the size of the first write. VxFS determines, based on the first write to a new file, the size of the first extent to allocate to the file. fcl_maxalloc operates only on Version 6 or higher disk layout file systems.Ĭhanges the default size of the initial extent. If the file system runs out of space before fcl_maxalloc is reached, the FCL is deactivated.Įither or both of the fcl_maxalloc or fcl_keeptime parameters must be set before the File Change Log can be activated. This process is referred to as 'punching a hole.' Holes are punched in the FCL file in 8K chunks. When the space allocated to the FCL file reaches the fcl_maxalloc value, the oldest FCL records are purged from the FCL and the extents nearest to the beginning of the FCL file are freed. The FCL file is a sparse file that grows as changes occur in the file system. Specifies the maximum amount of space that can be allocated to the VxFS File Change Log.

So appreciate your thoughts and thanks in advance for them! WIll these differences impact performance or can I leave them alone? Perhaps I'm being paranoid here but performance is really key on this server so I would like to cover all the bases if I can. I dont really know what these parameters do and if I need to set the values on the newly upgraded volume to be the same. Namely the fcl_maxalloc and initial_extent_size.

My question is : I see some differences between the values set with the volume created with 5.1, and the volume created originally from 5.0 (and upgraded successfully to version 7). I ran the same command on the volume I just upgraded to version 7 :įilesystem i/o parameters for /vx_testvol # vxtunefs /dev/vx/dsk/testdg5.1/testvol5.1įilesystem i/o parameters for /vx_testvol5.1 However I ran a vxtunefs on a volume I created using the vxvm 5.1 and saw the following : So, I upgraded it to version 7 so now its : # /opt/VRTS/bin/fstyp -v /dev/vx/dsk/testdg/testvol1 | grep -i version The following is the version output of the volume I have just imported : I have no probs importing the volumes of course, but I'm a bit concerned about having these different volumes version being used on the server having 5.1, specially from performance perspective. I am deporting some vxvm 5.0 MP3 volumes from another server and importing it to another server with vxvm version 5.1. I would like to have some opinion from the experts here on the following :

Veritas volume manager 3.5