asr.tech.notes

RAM disk in AIX AIX provides 'mkramdisk' command for producing a disk that resides in the RAM for very high I/O intensive applications like database. Here is a simple set of commands to create a ramdisk and a filesystem on top of it: create a RAM disk specifying the size          # mkramdisk 5G The system will assign the available RAM disk.  Since this is the first one, it will be called as ramdisk0 Check for the new disk         # ls -l /dev | grep -i ram If there isn't sufficient available memory, the mkramdisk command will warn about the same during the creation. Create and mount a filesystem on top of the ram disk     # mkfs -V jfs2 -o log=INLINE /dev/ramdisk0     # mkdir -p /ramdisk0     # mount -V jfs2 -o log=INLINE /dev/ramdisk0 /ramdisk0 The new filesystem will now be available like any other FS.   To remove a ram disk, unmount/remove the filesystem and us...

Setting MPIO parameters at various levels: 1.  At the physical adapter (FC) level on VIOS : For all fscsi devices on VIOS, set dyntrk=yes and fc_err_recvo=fast_fail fc_err_recov will fila any I/Os immediately if the adapter detects a link event, such as a lost link between a storage device and a switch.  The 'fast_fail' setting is recommended only for a dual VIOS configuraiton.   dyntrk attribute allows the VIOS to tolerate cabling changes in the SAN.   * Both VIOS need to be restarted for these changes to take effect.  2.  To all the disks on VIOS : alogrithm=load_balance (round robin - per best practices guide) reserve_policy=no_reserve hcheck_mode=nonactive hcheck_interval=60 3.   At the VIO Client leve l: vscsi devices in the client (virtual adapter) :  vscsi_path_to=30 All the devices in the client:   algorithm=failover reserve_policy=no_reserve hcheck_mode=nonactive - Specifying 'nonactive means that healthcheck commands are se...