HP OpenVMS systems documentation

The Availability Manager node fixes allow you to deliberately fail (crash) a node or to adjust cluster quorum.

To perform a node fix, follow these steps:

1. On the Node Summary, CPU, Memory, or I/O page, click the Fix menu.
2. Click Fix Options.

When you select the Crash Node option, the Availability Manager displays the Crash Node page, shown in Figure 6-1.

Figure 6-1 Crash Node Page

Recognizing a System Failure Forced by the Availability Manager

Because a user with suitable privileges can force a node to fail from the Data Analyzer by using the "Crash Node" fix, system managers have requested a method for recognizing these particular failure footprints so that they can distinguish them from other failures. These failures all have identical footprints: they are operator-induced system failures in kernel mode at IPL 8. The top of the kernel stack is similar the following display:

SP => Quadword system address Quadword data 1BE0DEAD.00000000 00000000.00000000 Quadword data TRAP$CRASH Quadword data SYS$RMDRIVER + offset

6.2.2 Adjust Quorum

The Adjust Quorum fix forces the node to refigure the quorum value. This fix is the equivalent of the Interrupt Priority C (IPC) mechanism used at system consoles for the same purpose. The fix forces the adjustment for the entire cluster so that each node in the cluster will have the same new quorum value.

The Adjust Quorum fix is useful when the number of votes in a cluster falls below the quorum set for that cluster. This fix allows you to readjust the quorum so that it corresponds to the current number of votes in the cluster.

When you select the Adjust Quorum option, the Availability Manager displays the page shown in Figure 6-2.

Figure 6-2 Adjust Quorum Page

To perform a process fix, follow these steps:

1. On the Memory or I/O page, right-click a process name.
2. Click Fix Options.
   The Availability Manager displays these Process tabs:

   Process General
   Process Memory
   Process Limits

3. Click one of these tabs to bring it to the front.
4. Click the down arrow to display the process fixes in this group, as shown in Figure 6-3, where the Process General tab has been chosen.

   Figure 6-3 Process General Options

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5. Select a process fix (for example, Process Priority, as shown in Figure 6-3,) to display a fix page.

Some of the fixes, such as Process Priority, require you to use a slider to change the default value. When you finish setting a new process priority, click Apply at the bottom of the page to apply that fix.

6.3.1 General Process Fixes

In most cases, a Delete Process fix deletes a process. However, if a process is waiting for disk I/O or is in a resource wait state (RWAST), this fix might not delete the process. In this situation, it is useless to repeat the fix. Instead, depending on the resource the process is waiting for, a Process Limit fix might free the process. As a last resort, reboot the node to delete the process.

When you select the Delete Process option, the Availability Manager displays the page shown in Figure 6-4.

Figure 6-4 Delete Process Page

After reading the explanation, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.1.2 Exit Image

Exiting an image on a node can stop an application that a user requires. Check the Single Process page first to determine which image is running on the node.

When you select the Exit Image option, the Availability Manager displays the page shown in Figure 6-5.

Figure 6-5 Exit Image Page

After reading the explanation in the page, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.1.3 Suspend Process

Suspending a process that is consuming excess CPU time can improve perceived CPU performance on the node by freeing the CPU for other processes to use. (Conversely, resuming a process that was using excess CPU time while running might reduce perceived CPU performance on the node.)

When you select the Suspend Process option, the Availability Manager displays the page shown in Figure 6-6.

Figure 6-6 Suspend Process Page

After reading the explanation, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.1.4 Resume Process

Resuming a process that was using excess CPU time while running might reduce perceived CPU performance on the node. (Conversely, suspending a process that is consuming excess CPU time can improve perceived CPU performance by freeing the CPU for other processes to use.)

When you select the Resume Process option, the Availability Manager displays the page shown in Figure 6-7.

Figure 6-7 Resume Process Page

After reading the explanation, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.1.5 Process Priority

If the priority of a compute-bound process is too high, the process can consume all the CPU cycles on the node, affecting performance dramatically. On the other hand, if the priority of a process is too low, the process might not obtain enough CPU cycles to do its job, also affecting performance.

When you select the Process Priority option, the Availability Manager displays the page shown in Figure 6-8.

Figure 6-8 Process Priority Page

To change the base priority for a process, drag the slider on the scale to the number you want. The current priority number is displayed in a small box above the slider. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new base priority, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.2 Process Memory Fixes

The following sections describe the Availability Manager fixes you can use to correct process memory problems:

• Purge Working Set
• Adjust Working Set

This fix purges the working set to a minimal size. You can use this fix to reclaim a process's pages that are not in active use. If the process is in a wait state, the working set remains at a minimal size, and the purged pages become available for other uses. If the process becomes active, pages the process needs are page-faulted back into memory, and the unneeded pages are available for other uses.

Be careful not to repeat this fix too often: a process that continually reclaims needed pages can cause excessive page faulting, which can affect system performance.

When you select the Purge Working Set option, the Availability Manager displays the page shown in Figure 6-9.

Figure 6-9 Purge Working Set Page

After reading the explanation on the page, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.2.2 Adjust Working Set

Adjusting the working set of a process might prove to be useful in situations similar to the following ones:

• If a process is page-faulting because of insufficient memory, you can reclaim unused memory from other processes by decreasing the working set of one or more of them.
• If a process is page-faulting too frequently because its working set is too small, you can increase its working set.

When you select the Adjust Working Set fix, the Availability Manager displays the page shown in Figure 6-10.

Figure 6-10 Adjust Working Set Page

To perform this fix, use the slider to adjust the working set to the limit you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new working set limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3 Process Limits Fixes

If a process is waiting for a resource, you can use a Process Limits fix to increase the resource limit so that the process can continue. The increased limit is in effect only for the life of the process, however; any new process is assigned the quota that was set in the UAF.

When you click the Process Limits tab, you can select any of the following options:

Direct I/O
Buffered I/O
AST
Open File
Lock
Timer
Subprocess
I/O Byte
Pagefile Quota

These fix options are described in the following sections.

6.3.3.1 Direct I/O Count Limit

You can use this fix to adjust the direct I/O count limit of a process. When you select the Direct I/O option, the Availability Manager displays the page shown in Figure 6-11.

Figure 6-11 Direct I/O Count Limit Page

To perform this fix, use the slider to adjust the direct I/O count to the limit you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new direct I/O count limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3.2 Buffered I/O Count Limit

Figure 6-12 Buffered I/O Count Limit Page

To perform this fix, use the slider to adjust the buffered I/O count to the limit you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new buffered I/O count limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3.3 AST Queue Limit

Figure 6-13 AST Queue Limit Page

To perform this fix, use the slider to adjust the AST queue limit to the number you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new AST queue limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3.4 Open File Limit

Figure 6-14 Open File Limit Page

To perform this fix, use the slider to adjust the open file limit to the number you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new open file limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3.5 Lock Queue Limit

Figure 6-15 Lock Queue Limit Page

To perform this fix, use the slider to adjust the lock queue limit to the number you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new lock queue limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3.6 Timer Queue Entry Limit

Figure 6-16 Timer Queue Entry Limit Page

To perform this fix, use the slider to adjust the timer queue entry limit to the number you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new timer queue entry limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3.7 Subprocess Creation Limit

Figure 6-17 Subprocess Creation Limit Page

To perform this fix, use the slider to adjust the subprocess creation limit of a process to the number you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new subprocess creation limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3.8 I/O Byte

Figure 6-18 I/O Byte Page

To perform this fix, use the slider to adjust the I/O byte limit to the number you want. You can also click the line above or below the slider to adjust the number by 1.

When you are satisfied with the new I/O byte limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.3.3.9 Pagefile Quota

Figure 6-19 Pagefile Quota Page

To perform this fix, use the slider to adjust the pagefile quota limit to the number you want. You can also click above or below the slider to adjust the fix value by 1.

When you are satisfied with the new pagefile quota limit, click Apply at the bottom of the page to apply the fix. A message displayed on the page indicates that the fix has been successful.

6.4 Performing Cluster Interconnect Fixes

Cluster interconnect fixes have been added to the Availability Manager beginning in Version 2.0. The following are categories of cluster interconnect fixes:

• Port adjust priority fix
• Circuit adjust priority fix
• LAN virtual circuit (VC) summary fixes
• LAN channel (path) fixes
• LAN device fixes

The following sections describe these types of fixes and tell how to access them and how to perform them. The descriptions also indicate whether or not the fix is currently available.

6.4.1 Port Adjust Priority Fix

To access the Port Adjust Priority fix, right-click a data item in the local port data display line (see Figure 4-3). The Availability Manager displays a popup menu with the Port Fix option.

This page (Figure 6-20) allows you to change the cost associated with this port, which, in turn, affects the routing of cluster traffic.

Figure 6-20 Port Adjust Priority Page

To access the Circuit Adjust Priority fix, right-click a data item in the local port data display line (see Figure 4-4). The Availability Manager displays a popup menu with the Circuit Fix option.

This page (Figure 6-21) allows you to change the cost associated with this circuit, which, in turn, affects the routing of cluster traffic.

Figure 6-21 Circuit Adjust Priority Page

To access LAN virtual circuit summary fixes, right-click a data item in the LAN Virtual Circuit Summary category (see Figure 4-6). The Availability Manager displays a popup menu with the following options:

• Channel Summary
• VC LAN Details...
• VC LAN Fix...

When you select VC LAN Fix..., the Availability Manager displays the first of several fix pages, the Maximum Transmit Window Size. By clicking Maximum Transmit Window Size, you can display a list of all the LAN VC summary fixes:

• Maximum Transmit Window Size
• Maximum Receive Window Size
• Checksumming
• Compression

These fixes are described in the following sections.

6.4.3.1 LAN VC Maximum Transmit Window Size Fix

Figure 6-22 LAN VC Maximum Transmit Window Size Page

6.4.3.2 LAN VC Maximum Receive Window Size Fix

Figure 6-23 LAN VC Maximum Receive Window Size Page