modify zfs process

Purpose

Enables you to query internal zFS counters and values. They are displayed on the system log. It also allows you to initiate or gather debugging information. The zFS PFS must be running to use this command.

Format

You can use any of the following formats for this command.

modify procname,query,{level | settings | threads[,{allwait | oldest}] | status| 
[{kn | vm | lfs | lock | storage | file | stkm | ctkc | svi  | iobydasd | dataset | all}]

modify procname,reset,{kn | vm | lfs | lock | storage | file | stkm | ctkc | svi | iobydasd | 
   dataset | all}

modify procname,trace,{reset | print}

modify procname,abort

modify procname,dump

modify procname,hangbreak

modify procname,unquiesce,aggregate_name

modify procname,nsvalidate[,print]

Parameters

procname

The name of the zFS PFS PROC. The default procname is ZFS.

command

The action that is performed on the zFS PFS. This parameter can have one of the following values:

query

Displays zFS counters or values.

level: Displays the zFS level for the zFS physical file system kernel. When running in a shared file system environment, level also displays the zFS sysplex level and the zFS XCF communication interface level (1, 2, 3 or 4). The zFS sysplex level is controlled by the IOEFSPRM sysplex configuration option. When the sysplex level is filesys, the default mount PARM (NORWSHARE or RWSHARE) is also displayed. (As of z/OS® V1R13, zFS always runs with sysplex=filesys.) For an example and more information, see Determining service levels.
settings: Displays the zFS configuration settings, which are based on the IOEFSPRM file and defaults.
threads[,{allwait | oldest }]: Displays the threads being monitored by the zFS hang detector. To display all zFS threads, use the modify zfs,query,threads,allwait command. The time of day values are shown in Greenwich mean time (GMT). To display the oldest thread of each system, use the modify zfs,query,threads,oldest command.
status: Displays zFS internal restart information.

<report>

One of the following report options; for details about these reports, see to Monitoring zFS performance.

kn: Displays the calls made to zFS from z/OS UNIX.
vm: Displays the user file cache including cache hit ratios, I/O rates and storage usage.
lfs: Displays the file system statistics including the performance of the zFS metadata caches, the vnode cache and the aggregate I/O statistics.
log: Displays the log statistics.
lock: Displays the lock contention values.
storage: Displays the zFS storage values.
file: Displays the requests per zFS file system and aggregate.
stkm: Displays the current server token manager (STKM) statistics.
ctkc: Displays the client calls to other systems. Output is only displayed when the zFS ctkc component on this system has sent a message to another system.
svi: Displays the calls from other systems to this server through the server vnode interface (SVI) component. Output is only displayed when the zFS svi component on this system has received a message from another system.
iobydasd: Displays the DASD that is currently attached by volume.
dataset: Displays zFS statistics about file systems.
all: Displays all the zFS counters.

reset

Resets zFS counters and consists of the following options:

kn: Resets the calls made to zFS from z/OS UNIX.
vm: Resets the user file cache including cache hit ratios, I/O rates and storage usage.
lfs: Resets the file system statistics including the performance of the zFS metadata caches, the vnode cache and the aggregate I/O statistics.
log: Resets the log statistics.
lock: Resets the lock contention values.
storage: Resets the zFS storage counters.
file: Resets the requests for zFS file system and aggregate.
stkm: Resets the server token manager (STKM) statistics.
ctkc: Resets the client call statistics.
svi: Resets the received calls from other systems statistics.
iobydasd: Resets the count of the DASD that is currently attached by volume.
dataset: Reset the zFS statistics about file systems.
all: Resets all the zFS counters to zero.

trace

Resets or prints the internal zFS trace table.

reset: Resets the internal (wrap around) trace table to empty.
print: Formats and sends the current trace table to the data set specified in the IOEFSPRM file trace_dsn entry. This data set must be pre-allocated as a PDSE with RECFM VB and LRECL 133. It must be large enough to hold the formatted trace table. See Performance and debugging for more information about the trace output data set.

abort

Causes zFS to dump and then perform an internal restart. The internal trace table is also printed to the data set specified in the IOEFSPRM file trace_dsn entry.

dump

Causes the zFS PFS to dump and to print the internal trace table to the data set specified in the IOEFSPRM file trace_dsn entry.

hangbreak

Causes a zFS internal restart; this produces the same result as issuing a modify zfs,abort command.

unquiesce

Causes a quiesced aggregate to become unquiesced. Only locally attached aggregates can be unquiesced using the modify unquiesce command. You must issue this command on the system that is the zFS owner of the aggregate. Use the z/OS UNIX zfsadm lsaggr command to determine which system is the zFS owner of the aggregate.

nsvalidate

Initiates the zFS namespace validation on the system where the command is entered. The modify nsvalidate command should only be used in a shared file system environment; typically, it is only used as a part of a recovery procedure when a problem with zFS is suspected. If the command finds an inconsistency, it might cause zFS to abort and internally restart the zFS address space on one or more systems to correct the zFS namespace inconsistency. The modify nsvalidate command consists of the following option:

print: The optional print parameter displays additional name space information that is obtained after validation.

Usage

The modify zfs command is used to display zFS counters or values and to initiate or gather debugging information. You cannot issue modify zfs commands during a zFS internal restart.

Privilege required

This command is a z/OS system command.

Examples

The following example queries all the zFS counters:

modify zfs,query,all

The following example resets the zFS storage counters:

modify zfs,reset,storage

The following example formats and sends the trace table to the data set specified in the IOEFSPRM file trace_dsn entry:

modify zfs,trace,print

The following example causes the zFS PFS to execute an internal restart:

modify zfs,abort

Related information

File:

IOEFSPRM

For details on stopping zFS, see the topic on Recycling z/OS UNIX System Services in z/OS MVS System Commands.