DKVIS(1) Co-Pilot" DKVIS(1)

dkvis - visualize disk I/O activity and performance

dkvis [-brVw] [-m maxrate] [-X ndisk] [-Y nctl] [pmview options] [diskid ...]

dkvis displays a three dimensional bar chart of disk activity. Each row of bars on the base plane represents a disk controller (or host adapter, or bus), and the bars within a row correspond to the disks attached to the controller.

The label to the left of each row identifies the common part of disk name for all disks in that row, e.g. dks3 for all IRIX SCSI disks attached to controller number 3.

The height of the bars is proportional to the activity.

The user can specify a list of disks as diskid arguments using the disk naming scheme reported by

$ pminfo -f disk.dev.total

e.g. hda or dks0d4 or sda or scsi/host1/bus0/target4/lun0/disc or 20000080e5114459/lun3/c2p1 depending on the type of disks. Alternatively, if the diskid argument contains one of the characters ^ or . or [ then diskid will be treated as a regular expression in the style of egrep(1) and the matching set of disk names will be used instead of diskid.

If one or more diskid arguments is specified, only the disks in this list are displayed in the view. The disks are grouped in the scene by controller as in the default scene when all disks are present.

dkvis generates a pmview(1) configuration file, and passes most command line options to pmview(1). Therefore, the command line options -A, -a, -C, -h, -n, -O, -p, -S, -t, -T, -Z and -z, and the user interface are described in the pmview(1) man page.

The dkvis specific options are:

Report the activity as data throughput in Kbytes per second rather than the default I/O operations per second (IOPS).
Use maxrate as the maximum activity from which utilization percentages are computed. This effectively specifies the height at which bars will be clipped. If -b is specified the default maximum value is 2048 Kbytes per second, otherwise the default maximum value is 150 IOPS.
Display the read activity. The default is to display the total (read and write) activity.
Verbose mode - output the generated pmview(1) configuration file.
Display the write activity. The default is to display the total (read and write) activity.
The default arrangement attempts to display up to 12 disks on the same controller in a single row. When more than 12 disks are associated with a controller, additional rows are created in an attempt to achieve a baseplane footprint for the scene that is as close to square as we can manage.

The -X option may be used to over-ride the default layout algorithm and force a scene in which each row contains no more than ndisk disks.

The default arrangement attempts to display disks for up to 16 controller rows in a single block. When more than 16 controller rows are present, additional blocks are created in an attempt to achieve a baseplane footprint for the scene that is as close to square as we can manage.

The -Y option may be used to over-ride the default layout algorithm and force a scene in which blocks are assigned such that each contains no more than nctl controller rows.

For backwards compatibility -R is a deprecated synonym for -Y .

Only one type of activity can be displayed per invocation of dkvis, hence -r and -w are mutually exclusive.

The behavior of pmchart(1) when launched from dkvis is dependent on the number of disks in each row. If there are more than 6 controllers then a separate chart will be generated for each column of disks. In other words, the first disk from each controller in one chart, the second disk in the next chart and so on. Otherwise a separate chart will be generated for each disk controller.

$PCP_VAR_DIR/config/pmlogger/config.dkvis
A pmlogger(1) configuration file for dkvis metrics.
$PCP_SHARE_DIR/lib/pmview-args
Shell procedures for parsing pmview(1) command line options.

Environment variables with the prefix PCP_ are used to parameterize the file and directory names used by PCP. On each installation, the file /etc/pcp.conf contains the local values for these variables. The $PCP_CONF variable may be used to specify an alternative configuration file, as described in pcp.conf(4).

dkstat(1), mpvis(1), nfsvis(1), pmchart(1), pmlogger(1), pmview(1), pcp.conf(4) and pcp.env(4).

The Disk and DiskCntrls views for pmchart(1).

Performance