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The MONITOR DISK command initiates monitoring of the DISK statistics class. The maximum number of disks that can be monitored for record output is 909, and for display and summary output is 1817.
MONITOR DISK
/qualifier[,...]
One or more qualifiers as described in the Command Qualifier Descriptions section.
/ALL
Specifies that a table of all available statistics (current, average, minimum, and maximum) is to be included in the display and summary output. For summary output, this qualifier is the default for all classes; otherwise, it is the default for all classes except CLUSTER, MODES, PROCESSES, STATES, SYSTEM, and VECTOR./AVERAGE
Specifies that a bar graph of average statistics is to be included in the display and summary outputs./CURRENT
Specifies that a bar graph of current statistics is to be included in the display and summary outputs. The /CURRENT qualifier is the default for the CLUSTER, MODES, STATES, SYSTEM, and VECTOR classes./ITEM=(keyword[,...])
Selects one or more data items for inclusion in display and summary outputs. If you specify two or more keywords, enclose them in parentheses, and separate them with commas. When the /ITEM qualifier is omitted, the default is /ITEM=OPERATION_RATE.The following table describes /ITEM qualifier keywords:
Keyword Description ALL Specifies that statistics on all data items collected for the disks are displayed on successive screens. OPERATION_RATE Specifies that I/O operation rate statistics are displayed for each disk. QUEUE_LENGTH Specifies that the number of I/O request packets being serviced (current or waiting) is displayed for each disk. /MAXIMUM
Specifies that a bar graph of maximum statistics is to be included in the display and summary outputs./MINIMUM
Specifies that a bar graph of minimum statistics is to be included in the display and summary outputs./PERCENT
/NOPERCENT (default)
Controls whether statistics are expressed as percent values in display and summary outputs. The /PERCENT qualifier is applicable only to the DISK, MODES, SCS, and STATES classes.
The DISK class is a component class. Data items for this class are collected for each mounted disk device in a single-node or cluster system. The DISK class consists of the following data items:
Data Item Description I/O Operation Rate Rate at which I/O operations occur on each disk. By comparing operation rates for all disks in the system, you can tell which disks are busy and which are idle. However, because this statistic does not provide information about the time required for individual operations, use discretion in interpreting it. I/O Request Queue Length Number of outstanding I/O request packets. Includes the request currently being serviced and those awaiting service. Note that, for greater precision, this item is always sampled at a 1-second interval, regardless of the value specified with the /INTERVAL command qualifier. The maximum number of disks that can be monitored is 909 for record output and 1817 for display or summary output. In previous versions, the limit was 799 disks for both types of output.
In the following example, typical of a cluster environment, note that each disk is identified by three elements:
- Disk name ending in a colon.
- Name of the cluster node through which the disk is accessed. This field appears only in the multiple-statistic display; it is not included in single-statistic displays or multifile summaries.
- Volume label.
In cluster configurations, the MSCP server software makes locally attached and HSC disks available to other nodes. A node uses remote access to a disk when it accesses the disk through another VAX node (using the MSCP server). A node uses direct access to a disk when it directly accesses a locally attached or HSC disk.
An "R" following the device name indicates that the displayed statistics represent I/O operations requested by nodes using remote access.
If an "R" does not appear after the device name, the displayed statistics represent I/O operations issued by nodes with direct access. These I/O operations might include those issued by the MSCP server on behalf of remote requests.
MONITOR> MONITOR DISK/ITEM=QUEUE_LENGTH
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This example, typical of a cluster environment, shows the number of I/O packets awaiting service or in service for each disk. Note that the device SAMPLE$DRA2 is the only device with a nonzero queue length. Because MONITOR samples queue lengths every second, regardless of the collection interval value, the precision of the data does not depend on the collection interval.
The MONITOR DLOCK command initiates monitoring of the DLOCK (distributed lock management) statistics class.
MONITOR DLOCK
/qualifier[,...]
One or more qualifiers as described in the Command Qualifier Descriptions section.
/ALL
Specifies that a table of all available statistics (current, average, minimum, and maximum) is to be included in the display and summary output. For summary output, this qualifier is the default for all classes; otherwise, it is the default for all classes except CLUSTER, MODES, PROCESSES, STATES, SYSTEM, and VECTOR./AVERAGE
Specifies that a bar graph of average statistics is to be included in the display and summary outputs./CURRENT
Specifies that a bar graph of current statistics is to be included in the display and summary outputs. The /CURRENT qualifier is the default for the CLUSTER, MODES, STATES, SYSTEM, and VECTOR classes./MAXIMUM
Specifies that a bar graph of maximum statistics is to be included in the display and summary outputs./MINIMUM
Specifies that a bar graph of minimum statistics is to be included in the display and summary outputs.
The DLOCK class is useful for monitoring the lock management subsystem in a cluster environment. The class consists of the following data items:
Data Item Description New ENQ Rate (Local) Rate of new lock (ENQ) requests that originate and are performed on this system New ENQ Rate (Incoming) Rate of new lock requests that originate on other systems and are performed on this system New ENQ Rate (Outgoing) Rate of new lock requests that originate on this system and are performed on another system Converted ENQ Rate (Local) Rate of lock (ENQ) conversion requests that originate and are performed on this system Converted ENQ Rate (Incoming) Rate of lock conversion requests that originate on other systems and are performed on this system Converted ENQ Rate (Outgoing) Rate of lock conversion requests that originate on this system and are performed on another system DEQ Rate (Local) Rate of unlock (DEQ) requests that originate and are performed on this system DEQ Rate (Incoming) Rate of unlock requests that originate on other systems and are performed on this system DEQ Rate (Outgoing) Rate of unlock requests that originate on this system and are performed on another system Blocking AST Rate (Local) Rate of lock manager blocking ASTs that originate and are performed on this system Blocking AST Rate (Incoming) Rate of lock manager blocking ASTs that originate on other systems and are performed on this system Blocking AST Rate (Outgoing) Rate of lock manager blocking ASTs that originate on this system and are performed on another system Directory Function Rate (Incoming) Rate of requests for locks being managed by this node Directory Function Rate (Outgoing) Rate of requests for locks being managed by other nodes Deadlock Message Rate Rate of incoming and outgoing messages required for deadlock detection
MONITOR> MONITOR DLOCK
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This example shows that most of the current lock management activity occurs locally, but that, at some point during the monitoring period, a significant amount of incoming activity occurred.
The MONITOR FCP command initiates monitoring of the File Control Primitive statistics class, which includes information about all Files-11 ancillary control processes (ACPs) and extended QIO processors (XQPs) on the local node.
MONITOR FCP
/qualifier[,...]
One or more qualifiers as described in the Command Qualifier Descriptions section.
/ALL
Specifies that a table of all available statistics (current, average, minimum, and maximum) is to be included in the display and summary output. For summary output, this qualifier is the default for all classes; otherwise, it is the default for all classes except CLUSTER, MODES, PROCESSES, STATES, SYSTEM, and VECTOR./AVERAGE
Specifies that a bar graph of average statistics is to be included in the display and summary outputs./CURRENT
Specifies that a bar graph of current statistics is to be included in the display and summary outputs. The /CURRENT qualifier is the default for the CLUSTER, MODES, STATES, SYSTEM, and VECTOR classes./MAXIMUM
Specifies that a bar graph of maximum statistics is to be included in the display and summary outputs./MINIMUM
Specifies that a bar graph of minimum statistics is to be included in the display and summary outputs.
The FCP class consists of the following data items, all of which are displayed as occurrences per second:
Data Item Description FCP Call Rate Rate of QIO requests received by the file system. Allocation Rate Rate of calls that caused allocation of disk space. Create Rate Rate at which new files were created. Disk Read Rate Rate of read I/O operations from disk by the file system. Disk Write Rate Rate of write I/O operations to disk by the file system. Volume Lock Wait Rate Rate of entry into a wait state due to contention for a volume synchronization lock. Volume synchronization locks are removed by the XQP during file creation, deletion, extension, and truncation operations. CPU Tick Rate Rate at which CPU time was used by the file system (in 10-millisecond ticks). File System Page Fault Rate Rate at which page faults occurred in the file system. Window Turn Rate Rate of file-map window misses. File Lookup Rate Rate of file name lookup operations in file directories. File Open Rate Rate at which files were opened. Erase Rate Rate of erase operations issued by the file system.
MONITOR> MONITOR /INTERVAL=10 FCP
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This example shows that the rate of files opened during the last 10-second collection interval was 2.0 (for a total of 20). The average rate since the MONITOR command was entered is 3.54; the highest rate achieved during any 10-second interval is 5.10, and the lowest rate of 2.0 occurred during the last interval.
The MONITOR FILE_SYSTEM_CACHE command initiates monitoring of the FILE_SYSTEM_CACHE statistics class.
MONITOR FILE_SYSTEM_CACHE
/qualifier[,...]
One or more qualifiers as described in the Command Qualifier Descriptions section.
/ALL
Specifies that a table of all available statistics (current, average, minimum, and maximum) is to be included in the display and summary output. For summary output, this qualifier is the default for all classes; otherwise, it is the default for all classes except CLUSTER, MODES, PROCESSES, STATES, SYSTEM, and VECTOR./AVERAGE
Specifies that a bar graph of average statistics is to be included in the display and summary outputs./CURRENT
Specifies that a bar graph of current statistics is to be included in the display and summary outputs. The /CURRENT qualifier is the default for the CLUSTER, MODES, STATES, SYSTEM, and VECTOR classes./MAXIMUM
Specifies that a bar graph of maximum statistics is to be included in the display and summary outputs./MINIMUM
Specifies that a bar graph of minimum statistics is to be included in the display and summary outputs.
The FILE_SYSTEM_CACHE class includes the following data items:
Data Item Description Directory FCB Hit% Percentage of directory file control block hits on the directory cache. The percentage value shown is the ratio of hits to the sum of hits plus misses. Directory FCB Attempt Rate Rate at which attempts were made to find directory file control blocks in the directory cache. Directory Data Hit% Percentage of directory data hits on the directory cache. The percentage value shown is the ratio of hits to the sum of hits plus misses. Directory Data Attempt Rate Rate at which attempts were made to find directory data in the directory cache. File Header Hit% Percentage of file header hits on the file header cache. The percentage value shown is the ratio of hits to the sum of hits plus misses. File Header Attempt Rate Rate at which attempts were made to find file headers in the file header cache. File ID Hit% Percentage of file identifier hits on the file ID cache. The percentage value shown is the ratio of hits to the sum of hits plus misses. File ID Cache Attempt Rate Rate at which attempts were made to find file identifiers in the file ID cache. Extent Cache Hit% Percentage of appropriate size extent hits on the extent cache. The percentage value shown is the ratio of hits to the sum of hits plus misses. Extent Cache Attempt Rate Rate at which attempts were made to find appropriate size extents in the extent cache. Quota Cache Hit% Percentage of quota entry hits on the quota cache. The percentage value shown is the ratio of hits to the sum of hits plus misses. Quota Cache Attempt Rate Rate at which attempts were made to find entries in the quota cache. Bitmap Cache Hit% Percentage of entry hits on the bitmap cache. The percentage value shown is the ratio of hits to the sum of hits plus misses. Bitmap Cache Attempt Rate Rate at which attempts were made to find entries in the bitmap cache. Note that all items shown in the FILE_SYSTEM_CACHE display except Dir FCB apply only to XQPs. The Dir FCB item applies to both XQPs and the ODS-1 ACP.
MONITOR> MONITOR FILE_SYSTEM_CACHE
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The cache hits and misses reflect the effectiveness of file system caching. Generally, the size of the cache affects the hit rate. The Attempt Rate is the sum of hits plus misses; the Hit% is the percentage of attempts that were successful.
Unlike other MONITOR data items, the averages for the hit percentages are not calculated based on previous hit percentages. Instead, these values are calculated based on the total number of hits and the total number of attempts on a cache since the beginning of the Monitor request. This provides more accurate average values for the hit percentage items.
The directory FCB cache is checked whenever a directory lookup is performed. Directory lookups can be performed on file open, creation, deletion, extension, or truncation. If the file control block associated with the directory is found in the cache, a hit is recorded. Otherwise, a miss is recorded. Both hits and misses are counted as attempts.
The directory data cache is checked whenever a file lookup is performed. Directory lookups may be performed on file open, creation, deletion, extension, or truncation. If an entry for the file being accessed is found in the directory data cache, a hit is recorded. Otherwise, a miss is recorded. Both hits and misses are counted as attempts.
The file header cache is checked on file open, close, creation, deletion, extension, or truncation. If the file header for the file being accessed is found in the file header cache, a hit is recorded. Otherwise, a miss is recorded. Both hits and misses are counted as attempts.
The file identification cache is a list of file identifiers that are removed on file creation and returned on file deletion. The File ID hits indicate file numbers successfully removed or returned to the file ID cache. Otherwise, a miss is recorded. Both hits and misses are counted as attempts.
The extent cache is checked on file creation, deletion, extension, and truncation. An attempt is made to allocate space from the extent cache during file creation or extension. During file creation, if sufficient size is found, a hit is recorded. If the desired size is not found, or an entry is forced to be split, an attempt is recorded. During file deletion, if the blocks were returned to the cache without the extent cache becoming too large, a hit is recorded. Otherwise, a miss is recorded. Both hits and misses are counted as attempts.
If quota checking is enabled, the quota cache is checked on file creation, deletion, extension, and truncation. If the desired entry (the identifier matching that of the requester) is found in the quota cache, a hit is recorded. Otherwise, a miss is recorded. Both hits and misses are counted as attempts.
The bitmap cache contains blocks from the storage bitmap file. This cache is accessed when the extent cache cannot satisfy requests for disk space. High rates indicate fragmented volumes.
Data items in the FILE_SYSTEM_CACHE display correspond to SYSGEN ACP/XQP parameters, as follows:
| FILE_SYSTEM_CACHE Item | ACP/XQP Parameters |
|---|---|
| Dir FCB | ACP_SYSACC |
| ACP_DINDXCACHE | |
| Dir Data | ACP_DIRCACHE |
| File Hdr | ACP_HDRCACHE |
| File ID | ACP_FIDCACHE |
| Extent | ACP_EXTCACHE |
| ACP_EXTLIMIT | |
| Quota | ACP_QUOCACHE |
| Bitmap | ACP_MAPCACHE |
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