IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

Chapter 7. Open systems servers - UNIX 223

The syntax and options are:

lquerypr [[-p]|[-c]|[-r]][-v][-V][-h/dev/PVname]

Flags:

–p If the persistent reservation key on the device is different from the

current host reservation key, it preempts the persistent reservation key

on the device.

–c If there is a persistent reservation key on the device, it removes any

persistent reservation and clears all reservation key registration on the

device.

–r Removes the persistent reservation key on the device made by this

host.

–v Displays the persistent reservation key if it exists on the device.

–V Verbose mode. Prints detailed message.

To query the persistent reservation on a device, type:

lquerypr -h /dev/vpath30

This command queries the persistent reservation on the device. If there is a persistent

reserve on a disk, it returns 0 if the device is reserved by the current host. It returns 1 if the

device is reserved by another host. Caution must be taken with the command, especially

when implementing preempt-abort or clear persistent reserve service action. With

preempt-abort service action not only the current persistent reserve key is preempted; it also

aborts tasks on the LUN that originated from the initiators that are registered with the

preempted key. With clear service action, both persistent reservation and reservation key

registrations are cleared from the device or LUN.

This command is useful if disk was attached to one system, and was not varied off leaving the

SCSI reserves on the disks, thus preventing another system from accessing them.

mkvg4vp, extendvg4vp, savevg4vp, and restvg4vp

mkvg4vp, extendvg4vp, savevg4vp, and restvg4vp have the same functionality as their

counterpart commands without the 4vp extension; use the 4vp versions when operating on

vpath devices. These commands will maintain pvids on vpaths and keep SDD working

properly.

It is a good idea to check periodically to make sure none of the volume groups are using

hdisks instead of vpaths. You can verify the path status several ways. Some commands are:

򐂰 lspv (look for hdisk with volume group names listed)

򐂰 lsvpcfg

򐂰 lsvg -p <vgname>

Remember to change any scripts you may have that call savevg or restvg and change the

calls to savevg4vp and restvg4vp.

7.6.1 HP-UX SDD commands

SDD for HP-UX adds the specific commands shown in Table 7-3 on page 224.

224 IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

Table 7-3 HP-UX SDD commands

showvpath

The showvpath command for HP-UX is similar to the lsvpcfg command for AIX. Use

showvpath to verify that an HP-UX vpath is using multiple paths to the DS6000. An example of

the output from showvpath is displayed in Example 7-22.

Example 7-22 showvpath command for HP-UX

#/opt/IBMsdd/bin/showvpath

vpath1:

/dev/rdsk/c12t0d0

/dev/rdsk/c10t0d0

/dev/rdsk/c7t0d0

/dev/rdsk/c5t0d0

vpath2:

/dev/rdsk/c12t0d1

Notice that vpath1 in the example has four paths to the DS6000. vpath2, however, has a

single point of failure since it is only using a single path.

hd2vp and vp2hd

The hd2vp and vp2hd commands work the same for HP-UX as they do for AIX. Use hd2vp to

convert volume groups to use vpaths and take advantage of the fail over and load balancing

Command Description

showvpath Lists the configuration mapping between SDD devices and

underlying disks.

chgvpath Configures SDD vpath devices. Updates the information in

/etc/vpath.cfg and /etc/vpathsave.cfg. The -c option updates the

configuration file. The -r option updates the device configuration

without a system reboot.

defvpath Second part of the chgvpath command configuration during startup

time.

datapath SDD driver console command tool.

rmvpath [-all, -vpathname] Removes SDD vpath devices from the configuration.

hd2vp Converts a volume group from DS6000 hdisks

into SDD vpaths.

get_root_disks Generates a file called /etc/vpathexcl.cfg to exclude bootable disks

from the SDD configuration.

querysn Lists all disk storage devices by serial number.

pathtest Debug tool.

gettrace Debug tool that gets trace information.

vp2hd Converts a volume group from SDD vpaths

into DS6000 hdisks.

Tip: You can use the output from showvpath to modify iostat or sar information to report

stats based on vpaths instead of hdisks. Gather iostats to a file, and then replace the disk

names with the corresponding vpaths.