Document revision date: 30 March 2001

By clicking the I/O tab on any OpenVMS node data page, you can display a page that contains summaries of accumulated I/O rates. In the top pane, this summary covers all CPUs; in the bottom pane, this summary is per process.

From the View menu, you can also choose to display (in the bottom pane) a list of page and swap files.

3.2.4.1 OpenVMS I/O Summaries

The OpenVMS I/O Summaries display the rate (per second) at which I/O transfers take place, including paging write I/O (WIO), direct I/O (DIO), and buffered I/O (BIO). In the top pane, the summary is for all CPUs; in the bottom pane, the summary is for one process.

When you double-click a data item under the DIO or BIO heading on the Node pane, or if you click the I/O tab, the Availability Manager displays, by default, the OpenVMS I/O Summaries (Figure 3-10).

Figure 3-10 OpenVMS I/O Summaries Page

The graph in the top pane represents the percentage of thresholds for the types of I/O shown in Table 3-4. The table also shows the event that is related to each data item. Refer to Section 6.5 for information about setting event thresholds.

Table 3-4 I/O Data Displayed

Type of I/O	I/O Description	Related Event
Paging Write I/O Rate (WIO)	Rate of write I/Os to one or more paging files.	HIPWIO
Direct I/O Rate (DIO)	Transfers are from the pages or pagelets containing the process buffer that the system locks in physical memory to the system devices.	HIDIOR
Buffered I/O Rate (BIO)	Transfers are for the process buffer from an intermediate buffer from the system buffer pool.	HIBIOR
Total Page Faults	Total of hard and soft page faults on the system, as well as peak values seen during an Availability Manager session.	HITTLP
Hard Page Faults	Total of hard page faults on the system.	HIHRDP
System Page Faults	Page faults that are taken from kernel processes.	HISYSP

In addition, current and peak values are listed for each type of I/O. Values that exceed thresholds set by the events indicated in the table are displayed in red on the screen. Appendix B describes OpenVMS and Windows NT events.

To the right of the graph, the following values are listed:

Value	Description
Threshold	Defined in Event Properties.
Current	Current value or rate.
Peak	Highest value of rate seen since start of data collection.

The bottom pane displays summary accumulated I/O rates on a per-process basis. The following data is displayed:

Data	Description
PID	Process identifier. A 32-bit value that uniquely identifies a process.
Process Name	Name of the current process.
DIO Rate	Direct I/O rate. The rate at which I/O transfers occur between the system devices and the pages or pagelets that contain the process buffer that the system locks in physical memory.
BIO Rate	Buffered I/O rate. The rate at which I/O transfers occur between the process buffer and an intermediate buffer from the system buffer pool.
PIO Rate	Paging I/O rate. The rate of read attempts necessary to satisfy page faults (also known as page read I/O or the hard fault rate).
Open Files	Number of open files.
DIO Avail	Direct I/O limit remaining. The number of remaining direct I/O limit operations available before the process reaches its quota. DIOLM quota is the maximum number of direct I/O operations a process can have outstanding at one time.
BIO Avail	Buffered I/O limit remaining. The number of remaining buffered I/O operations available before the process reaches its quota. BIOLM quota is the maximum number of buffered I/O operations a process can have outstanding at one time.
BYTLM	The number of buffered I/O bytes available before the process reaches its quota. BYTLM is the maximum number of bytes of nonpaged system dynamic memory that a process can claim at one time.
Files	Open file limit remaining. The number of additional files the process can open before reaching its quota. The FILLM quota is the maximum number of files that can be opened simultaneously by the process, including active network logical links.

When you double-click a PID on the lower part of an OpenVMS CPU Process (Figure 3-7), Memory (Figure 3-9), or I/O (Figure 3-10) page, the Availability Manager displays an OpenVMS Single Process, where you can click tabs to display specific data about one process. This data includes a combination of data from the CPU Process, Memory, and I/O pages, as well as data for specific quota utilization, current image, and queue wait time. These pages are described in Section 3.2.9.

3.2.4.2 OpenVMS I/O Page/Swap Files

Click I/O Page/Swap Files on the I/O page View menu to select this option. The Availability Manager displays an OpenVMS I/O Page/Swap Files page (Figure 3-11).

Figure 3-11 OpenVMS I/O Page/Swap Files Page

The top pane displays the same information displayed in the OpenVMS I/O Summary (Figure 3-10). The bottom pane displays the following data:

Data	Description
Host Name	Name of the node on which the page or swap file resides.
File Name	Name of the page or swap file. For secondary page or swap files, the file name is obtained by a special AST to the job controller on the remote node. The Availability Manager makes one attempt to retrieve the file name.
Used	Number of used blocks in the file.
% Used	Of the available blocks in each file, the percentage that has been used.
Total	Total number of blocks in the file.
Reservable	The number of reservable blocks in each page or swap file currently installed. Reservable blocks are blocks that might be logially claimed by a process for future physical allocation. A negative value indicates that the file might be overcommitted. Although a negative value is not an immediate concern, it indicates that the file might become overcommitted if physical memory becomes scarce.

3.2.5 Disk Summaries

The Disk tab allows you to display disk pages that contain data about availability, count, and errors of disk devices on the system. OpenVMS disk data displays differ from those for Windows NT nodes, as described in the following sections.

On OpenVMS pages, the View menu lets you choose the following disk summaries:

• Disk Status Summary
• Disk Volume Summary

Also, on the Disk Status Summary, you can double-click a device name to display a Single Disk Summary page.

3.2.5.1 OpenVMS Disk Status Summary

When you click the Disk tab on the OpenVMS Node Summary page, the Availability Manager displays the default disk page, the OpenVMS Disk Status Summary (Figure 3-12). This page displays disk device data, including path, volume name, status, and mount, transaction, error, and resource wait counts.

Figure 3-12 OpenVMS Disk Status Summary

This summary displays the following data:

Heading	Description
Device Name	Standard OpenVMS device name that indicates where the device is located, as well as a controller or unit designation.
Host Path	Primary path (node) from which the device receives commands.
Volume Name	Name of the mounted media.
Status	One or more of the following disk status values: Alloc Disk is allocated to a specific user. CluTran Disk status is uncertain because of a cluster state transition in progress. Dismount Disk in process of dismounting; may be waiting for a file to close. Foreign Disk is mounted with the /FOREIGN qualifier. Invalid Disk is in an invalid state (most likely Mount Verify Timeout). MntVerify Disk is waiting for a mount verification. Mounted Disk is logically mounted by a MOUNT command. Offline Disk is no longer physically mounted in device drive. Online Disk is physically mounted in device drive. Shadow Set Member Disk is a member of a shadow set. Unavailable Disk is set to unavailable. Wrong Volume Disk was mounted with the wrong volume name. Wrtlck Disk is mounted and write locked.
Error	Number of errors generated by the disk (a quick indicator of device problems).
Trans	Number of in-progress file system operations for the disk.
Mount	Number of nodes that have the specified disk mounted.
Rwait	Indicator that a system I/O operation is stalled, usually during normal recovery from a connection failure or during volume processing of host-based shadowing.

3.2.5.2 OpenVMS Single Disk Summary

To collect single disk data and display the data on the Single Disk Summary, double-click a device name on the Disk Status Summary. Figure 3-13 is an example of a Single Disk Summary page. The display interval of the data collected is 5 seconds.

Figure 3-13 OpenVMS Single Disk Summary Page

This summary displays the following data:

Data	Description
Node	Name of the node.
Status	Status of the disk: mounted, online, offline, and so on.
Errors	Number of errors on the disk.
Trans	Number of in-progress file system operations on the disk (number of open files on the volume).
Rwait	Indication of an I/O stalled on the disk.
Free	Number of free disk blocks on the volume. An (M) after the free block count indicates this node holds the lock on the volume that DECamds uses to obtain the true free block count on the volume. Other nodes might not have accessed the disk, so their free block count might not be up to date.
QLen	Average number of operations in the I/O queue for the volume.
OpRate	Each node's contribution to total OpRate for the disk.

3.2.5.3 OpenVMS Disk Volume Summary

When you select the Status Summary option from the View menu on the OpenVMS Node Summary page, the Availability Manager displays the OpenVMS Disk Status Summary (Figure 3-14). This page displays disk volume data, including path, volume name, disk block utilization, queue length, and operation rate.

Figure 3-14 OpenVMS Disk Volume Summary Page

This summary displays the following data:

Data	Description
Device Name	Standard OpenVMS device name that indicates where the device is located, as well as a controller or unit designation.
Host Path	Primary path (node) from which the device receives commands.
Volume Name	Name of the mounted media.
% Used	Percentage of the number of volume blocks in use in relation to the total volume blocks available.
Free	Number of blocks of volume space available for new data.
Queue	Average number of I/O operations pending for the volume (an indicator of performance; less than 1.00 is optimal).
OpRate	Operation rate for the most recent sampling interval. The rate measures the amount of activity on a volume. The optimal load is device specific.

Windows NT Logical and Physical Disk Summaries

On Windows NT nodes, the View menu lets you choose the following summaries:

• Logical Disk Summary
• Physical Disk Summary

A logical disk is the user-definable set of partitions under a drive letter. The Windows NT Logical Disk Summary displays logical disk device data, including path, label, percentage used, free space, and queue statistics.

To display the Logical Disk Summary page, follow these steps:

1. Double-click a node name in the Node pane to display the Windows NT Node Summary.
2. Click the Disk tab on the Windows NT Node Summary.

The Availability Manager displays the Windows NT Logical Disk Summary page (Figure 3-15).

Figure 3-15 Windows NT Logical Disk Summary Page

This summary displays the following data:

Data	Description
Disk	Drive letter, for example, c:, or Total, which is the summation of statistics for all the disks.
Path	Primary path (node) from which the device receives commands.
Label	Identifying label of a volume.
Type	File system type; for example, FAT or NTFS.
% Used	Percentage of disk space used.
Free	Amount of free space available on the logical disk unit.
Current Queue	Number of requests outstanding on the disk at the time the performance data is collected. It includes requests in progress at the time of data collection.
Average Queue	Average number of both read and write requests that were queued for the selected disk during the sample interval.
Transfers/Sec	Rate of read and write operations on the disk.
KBytes/Sec	Rate data is transferred to or from the disk during write or read operations. The rate is displayed in kilobytes per second.
% Busy	Percentage of elapsed time that the selected disk drive is busy servicing read and write requests.

3.2.5.5 Windows NT Physical Disk Summary

A physical disk is hardware used on your computer system. The Windows NT Physical Disk Summary displays disk volume data, including path, label, queue statistics, transfers, and bytes per second.

To display the Windows NT Physical Disk Summary, follow these steps:

1. Click the View menu on the Windows NT Logical Disk Summary.
2. Click the Physical Disk Summary menu option.

The Availability Manager displays the Windows NT Physical Disk Summary page (Figure 3-16).

Figure 3-16 Windows NT Physical Disk Summary Page

This page displays the following data:

Data	Description
Disk	Drive number, for example, 0, 1, 2 or Total, which is the summation of statistics for all the disks.
Path	Primary path (node) from which the device receives commands.
Current Queue	Number of requests outstanding on the disk at the time the performance data is collected; it includes requests in service at the time of data collection.
Average Queue	Average number of read and write requests that were queued for the selected disk during the sample interval.
Transfers/Sec	Rate of read and write operations on the disk. The rate is displayed in kilobytes per second.
KBytes/Sec	Rate bytes are transferred to or from the disk during read or write operations. The rate is displayed in kilobytes per second.
% Busy	Percentage of elapsed time the selected disk drive is busy servicing read and write requests.
% Read Busy	Percentage of elapsed time the selected disk drive is busy servicing read requests.
% Write Busy	Percentage of elapsed time the selected disk drive is busy servicing write requests.

3.2.6 OpenVMS Lock Contention

When you select the Lock Contention tab on the OpenVMS Node Summary page, the Availability Manager displays the OpenVMS Lock Contention. This page, shown in Figure 3-17, displays each resource in the group you have selected for which a potential lock contention problem exists.

Figure 3-17 OpenVMS Lock Contention Page

This page displays the following data:

Data	Description
Resource Name	Resource name associated with the $ENQ system service call. An ellipsis (...) indicates an unprintable character.
Master Node	Node on which the resource is mastered.
Parent Resource	Name of the parent resource. If no name is displayed, the resource listed is the parent resource.
Duration	Amount of time elapsed since the Availability Manager first detected the contention situation.
Status	Status of the lock. See the $ENQ(W) description in the OpenVMS System Services Reference Manual.

When you double-click a data item under these headings, the Availability Manager displays the following data:

Data	Description
Node	Node name on which the lock is granted.
Process Name	Name of the process owning the blocking lock.
LKID	Lock ID value (which is useful with SDA).
Mode	One of the following modes at which the lock is granted or requested: EX, CW, CR, PW, PR, NL.
Duration	Length of time the lock has been in the current queue (since the console application found the lock).
Flags	Flags specified with the $ENQ(W) request.

Data is displayed in one of three colors:

Color	Meaning
Green	Granted
Yellow	Converting
Pink	Waiting

To interpret the information displayed on the OpenVMS Lock Contention Summary, you should understand OpenVMS lock management services. For more information, see the OpenVMS System Services Reference Manual.

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