sysstat bug fix update

An updated sysstat package that fixes various bugs is now available.

The sysstat package provides the sar and iostat commands. These commands
enable system monitoring of disk, network, and other I/O activity.

This updated sysstat package fixes the following bugs:

* on systems with long up-times, several variable overflows caused the "sar
-w" command to eventually, and erroneously, report the total number of
context switches per second (cswch/s) as 0. With this update, the variable
overflows have been addressed and cswch/s values are reported correctly
regardless of how long a system has been running. (BZ#435683)

* the iostat man page contained a repeated error concerning captured block
device input and output (I/O) data. iostat records multiple values
including read requests per second (r/s); write requests per second (w/s);
sectors read per second (rsec/s); sectors written per second (wsec/s);
kilobytes read per second (rkB/s); and kilobytes written per second
(wkB/s). The documentation previously suggested iostat recorded the number
of requests or writes per second without qualification.

This is incorrect. Values in these fields are updated when requests are
inserted into the request queue. For read and write requests, this means
iostat records the number of completed requests. For sector reads & writes
and kilobyte reads & writes, however, it means iostat records the number of
completed and in-progress requests.

Depending on the hardware configuration and I/O workload, there can be a
measurable delay between the addition of a request to the request queue and
the completion of that request. Consequently, the number of sectors or
kilobytes recorded as read or written may be ahead of the actual reads and
writes. With this update, the man page has been corrected to document the
'in-progress' nature of iostat's record. (BZ#450115)

* an uptime variable overflow caused the sar utility to report inaccurate
CPU usage totals on Itanium®-based systems. This presented as a missing
line followed by a line showing 0.00 in every field; %user, %nice, %system,
%iowait, and %idle. With this update, the uptime variable overflow has been
fixed and, consequently, the sar utility reports accurately. (BZ#453050)

* the data for TTY device activity reports was not generating correctly.
Consequently, the command "sar -y" failed, returning the error: "Requested
activities not available in file". In this updated package, sar has been
corrected so the -y option outputs the TTY device activity as documented.
(BZ#458237)

* running "iostat -kxn" would, after approximately 30 minutes, produce too
many open file descriptors, causing iostat to fail with a "too many files
open" error. With this update, the number of open file descriptors is kept
below ten, ensuring iostat does not fail. (BZ#475100)

* by default, /etc/sysconfig/sysstat is as follows:

# How long to keep log files (days), maximum is a month
HISTORY=7

The /var/lib/sa2 script deletes /var/log/sa* files > $HISTORY days old. The
phrase 'maximum is a month' is, however, ambiguous and did not reflect
actual behavior. If "HISTORY=31", for example, most sa* files are never
deleted. In this circumstance, running "sar -f /var/log/sa21" did not
return the log for the 21st of the current month: it returned the log for
the 21st of every month since the system was booted. With this update,
HISTORY has been given a hard limit: 26. (Higher values are treated as 26.)
This maximum ensures February log files are not retained with their
equivalent dates in March. (BZ#475255)

All sysstat users are advised to upgrade to this updated package, which
resolves these issues.

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259

453050 - file_stats[curr, prev].cpu_* values of sar show innacurate CPU usage.
475100 - iostat -kxn 2 crashes after 30 minutes

sadc, sar