The Improved OpenVMS File System This kit is an improved OpenVMS file system (XQP+). The XQP+ provides new features to improve the performance of your PATHWORKS file server: ___________________________________________________________ New_Feature______Description_______________________________ Multi-threading Allows the PATHWORKS file server to perform up to eight OpenVMS file system operations in parallel. Improved Allows the OpenVMS file system to process concurrency multiple file create operations on a single disk in parallel. Normally in a VMScluster, only one process can create files on a disk at a time. Asynchronous Allows the PATHWORKS file server to cache writes return control to the PATHWORKS client before completing certain OpenVMS file system operations. This improves the response time for accessing files from the file server. Multi-block Reduces the time the OpenVMS file system bitmap reads spends allocating disk space. ___________________________________________________________ ________________________ Note ________________________ Currently, you can install the XQP+ only on OpenVMS VAX V5.5-2 and V6.0 systems. Future releases of both OpenVMS VAX and OpenVMS Alpha AXP will include the XQP+ file system enhancements. ______________________________________________________ Controlling the New Features Three of the new features of the XQP+ are controlled by the following system parameters on an OpenVMS VAX V5.5-2 system: ___________________________________________________________ Parameter_______Description________________________________ VMSD2 Enables and disables multi-threading and improved concurrency. ___________________________________________ Value___Result_____________________________ 8 Enables multi-threading and improved concurrency. 32769 Disables multi-threading and improved concurrency. ___________________________________________ Note that a disk only benefits from the improved concurrency if VMSD2 is set to 8 when the disk is mounted. ACP_WRITEBACK Enables and disables asynchronous cache writes. ___________________________________________ Value___Result_____________________________ 1 Enables asynchronous cache writes. 0 Disables asynchronous cache writes. ___________________________________________ ___________________________________________________________ The same features are controlled by the following system parameters on an OpenVMS VAX V6.0 system: ___________________________________________________________ Parameter_______Description________________________________ XQPCTLD1 Enables and disables multi-threading. ___________________________________________ Value___Result_____________________________ 8 Enables multi-threading. 0 Disables multi-threading. ___________________________________________ XQPCTL2 Enables and disables improved concurrency. ___________________________________________ Value___Result_____________________________ 1 Enables improved concurrency. 0 Disables improved concurrency. ___________________________________________ ACP_WRITEBACK Enables and disables asynchronous cache writes. ___________________________________________ Value___Result_____________________________ 1 Enables asynchronous cache writes. 0 Disables asynchronous cache writes. ___________________________________________ ___________________________________________________________ On each system in a VMScluster, you should: o Set each parameter to the same value. For example, if the installation procedure sets ACP_WRITEBACK to 1, set ACP_WRITEBACK to 1 on each system. o Update the MODPARAMS.DAT file so that it reflects the new parameter values. VMSclusters Running OpenVMS VAX V5.5-2 and V6.0 In a VMScluster, OpenVMS VAX V5.5-2 and V6.0 systems that run their respective versions of the XQP+ can coexist. Make sure, however, that all the systems in the cluster run the XQP+. Installing and Deinstalling the XQP+ Use the VMSINSTAL command procedure to install the XQP+. For information on VMSINSTAL, see the OpenVMS System Manager's Manual. To make sure you can restore the original XQP at any time, the installation procedure copies the original XQP and stores it in SYS$COMMON:[SYSEXE]F11BXQP_OLD.EXE. If you want to remove the XQP+ and restore the original XQP, you can use the PWF11X$DEINSTAL command procedure, which is installed with the XQP+. To deinstall the XQP+, follow these steps: 1. Run the deinstallation procedure for each system disk on which you installed the XQP+: $ @SYS$UPDATE:PWF11X$DEINSTAL The deinstallation procedure will fail if it cannot find the original XQP. 2. Reset system parameters to their default values on every system in your VMScluster: ----------------------------------------------------- On ... The default values are ... ----------------------------------------------------- An OpenVMS V5.5-2 system VMSD2=0, ACP_WRITEBACK=1. An OpenVMS V6.0 system XQPCTLD1=0, XQPCTL2=0, ACP_WRITEBACK=1. ----------------------------------------------------- 3. Reboot the system. Precautions, Concerns, and Known Problems o Location of the current XQP If the installation procedure finds a copy of the XQP in SYS$SPECIFIC:[SYSEXE], the XQP+ will not install. The procedure only replaces the file F11BXQP.EXE if it is in SYS$COMMON:[SYSEXE], and there are no copies of it in SYS$SPECIFIC:[SYSEXE]. o VMSclusters running both the XQP+ and the original XQP Under very exceptional circumstances, deadlocks have occurred in VMSclusters running both the XQP+ and the original XQP. These deadlocks have only occurred under extremely heavy loads created by special XQP stressing software. The deadlocks have not occurred under typical system loads, and do not occur with VMSclusters running the XQP+ on all systems. To accommodate this problem, the XQP+ installation procedure asks you if you are going to install the XQP+ on all systems in your VMScluster. If you answer No, the procedure disables multi-threading and improved concurrency. In this case, you should disable multi-threading and improved concurrency on all the other systems in your VMScluster. o To control improved concurrency and multi-threading, the V6.0 parameters XQPCTLD1 and XQPCTL2 replace the V5.5-2 parameter VMSD2. The following table shows you how to set these parameters consistently in a VMScluster that has both V5.5-2 and V6.0 systems. __________________________________________________________ If you want On a V5.5-2 On a V6.0 to ..._______________system ...__________system ..._______ Enable improved Set VMSD2 to 8 Set XQPCTL2 to 1 concurrency and and XQPCTLD1 to multi-threading 8. Disable improved Set VMSD2 to Set XQPCTL2 to 0 concurrency and 32769 and XQPCTLD1 to multi-threading 0. __________________________________________________________ o Upgrading OpenVMS VAX Systems If you upgrade your OpenVMS VAX system from V5.5-2 to V6.0, you must reinstall the XQP+.