The release of VxFS patch PHKL_44844 in conjunction with the VM patch PHKL_44816 provides a new interface to exclude the VxFS inode cache from this periodic memory freeing operations.  The VxFS patch leverages this interface to avoid unnecessary freeing of inodes due to periodic memory garbage collection, when there is no memory pressure.

 

Note that BOTH PHKL_44844 and PHKL_44816 are required to fully benefit from the vx_ifree_timelag=-1 setting behavior.

vx_ifree_timelag can be tuned via the sam or kctune commands. Changes in the tunable are dynamic and take effect immediately.

For more information about the behavior of setting vx_ifree_timelag to -1 on HP-UX, please refer to VxFS patch PHKL_44844 (from Veritas) and Virtual Memory patch PHKL_44816 (from HPE) for details.

Setting value of the vx_ifree_timelag to -1 on HPUX is not effective without applying additional patches. The tunable vx_ifree_timelag is used to manage the time taken to free the memory allocated to an inode after the inode is placed on the freelist. Below is a description of vx_ifree_timelag Veritas™ File System Administrator's Guide. “The default value of vx_ifree_timelag is 0. By setting vx_ifree_timelag to 0, the inode free time lag is autotuned to 600 seconds. Specifying negative one (-1) stops the freeing of inode space; no further inode allocations are freed until the value is changed back to a value other than negative one.” On HP-UX platform, the HP-UX memory garbage collector is allowed to request a shrink on the VxFS inode cache if needed, even when vx_ifree_timelag is set to -1. Inodes will still be freed in order to shrink the inode cache even when vx_ifree_timelag is -1. The VxFS inode cache could not be manually excluded from periodic HPUX garbage collection, negating the benefit of this setting.