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Docs update
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vlnb committed Apr 19, 2011
1 parent 8d25be1 commit e5c4fe0
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4 changes: 3 additions & 1 deletion AskingQuestions
Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,9 @@ target and SCST configurations.
Please, NEVER send dmesg output without timestamps, because timestamps
are very important to see the whole picture. You should either enable
CONFIG_PRINTK_TIME kernel compile option, or use kernel logs your system
logger stored for you in /var/log.
logger stored for you in /var/log. In case if you enabled a trace option
producing a lot of log data, you should make NOT CORRUPTED logs as
described in section "Dealing with massive logs" of the SCST README.

******************************************************
******************************************************
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4 changes: 3 additions & 1 deletion iscsi-scst/AskingQuestions
Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,9 @@ target and SCST configurations.
Please, NEVER send dmesg output without timestamps, because timestamps
are very important to see the whole picture. You should either enable
CONFIG_PRINTK_TIME kernel compile option, or use kernel logs your system
logger stored for you in /var/log.
logger stored for you in /var/log. In case if you enabled a trace option
producing a lot of log data, you should make NOT CORRUPTED logs as
described in section "Dealing with massive logs" of the SCST README.

******************************************************
******************************************************
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4 changes: 3 additions & 1 deletion qla2x00t/qla2x00-target/AskingQuestions
Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,9 @@ target and SCST configurations.
Please, NEVER send dmesg output without timestamps, because timestamps
are very important to see the whole picture. You should either enable
CONFIG_PRINTK_TIME kernel compile option, or use kernel logs your system
logger stored for you in /var/log.
logger stored for you in /var/log. In case if you enabled a trace option
producing a lot of log data, you should make NOT CORRUPTED logs as
described in section "Dealing with massive logs" of the SCST README.

******************************************************
******************************************************
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4 changes: 3 additions & 1 deletion scst/AskingQuestions
Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,9 @@ target and SCST configurations.
Please, NEVER send dmesg output without timestamps, because timestamps
are very important to see the whole picture. You should either enable
CONFIG_PRINTK_TIME kernel compile option, or use kernel logs your system
logger stored for you in /var/log.
logger stored for you in /var/log. In case if you enabled a trace option
producing a lot of log data, you should make NOT CORRUPTED logs as
described in section "Dealing with massive logs" of the SCST README.

******************************************************
******************************************************
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55 changes: 36 additions & 19 deletions scst/README
Original file line number Diff line number Diff line change
Expand Up @@ -414,7 +414,9 @@ following entries:
BLOCKIO or NULLIO.

- trace_level - allows to enable and disable various tracing
facilities. See content of this file for help how to use it.
facilities. See content of this file for help how to use it. See also
section "Dealing with massive logs" for more info how to make correct
logs when you enabled trace levels producing a lot of logs data.

- version - read-only attribute, which allows to see version of
SCST and enabled optional features.
Expand Down Expand Up @@ -481,7 +483,9 @@ SCST dev handlers can have the following common entries:
handlers).

- trace_level - allows to enable and disable various tracing
facilities. See content of this file for help how to use it.
facilities. See content of this file for help how to use it. See also
section "Dealing with massive logs" for more info how to make correct
logs when you enabled trace levels producing a lot of logs data.

- type - SCSI type of devices served by this dev handler.

Expand Down Expand Up @@ -799,7 +803,9 @@ entries:
of the corresponding devices.

- trace_level - allows to enable and disable various tracing
facilities. See content of this file for help how to use it.
facilities. See content of this file for help how to use it. See also
section "Dealing with massive logs" for more info how to make correct
logs when you enabled trace levels producing a lot of logs data.

- mgmt - main management entry, which allows to add/delete VDISK
devices with the corresponding type.
Expand Down Expand Up @@ -1037,6 +1043,29 @@ IMPORTANT: Some disk and partition table management utilities don't support
work with files on such file system.


Dealing with massive logs
-------------------------

If you want to enable using "trace_level" file logging levels, which
produce a lot of events, like "debug", to not loose logged events you
should also:

* Increase in .config of your kernel CONFIG_LOG_BUF_SHIFT variable
to much bigger value, then recompile it. For example, value 25 will
provide good protection from logging overflow even under high volume
of logging events. To use it you will need to modify the maximum
allowed value for CONFIG_LOG_BUF_SHIFT in the corresponding Kconfig
file to 25 as well.

* Change in your /etc/syslog.conf or other config file of your favorite
logging program to store kernel logs in async manner. For example,
you can add in rsyslog.conf line "kern.info -/var/log/kernel" and
add "kern.none" in line for /var/log/messages, so the resulting line
would looks like:

"*.info;kern.none;mail.none;authpriv.none;cron.none /var/log/messages"


Persistent Reservations
-----------------------

Expand Down Expand Up @@ -1667,22 +1696,10 @@ It contains the following entries.
- "trace_level" file, which allows to read and set trace (logging) level
for SCST. Also this file allows to dump persistent reservations
information about some device in the log file. See
/proc/scsi_tgt/help file for list of commands and trace levels. If
you want to enable logging options, which produce a lot of events,
like "debug", to not loose logged events you should also:

* Increase in .config of your kernel CONFIG_LOG_BUF_SHIFT variable
to much bigger value, then recompile it. For example, value 25
will provide good protection from logging overflow even under
high volume of logging events, but to use it you will need to
modify the maximum allowed value for CONFIG_LOG_BUF_SHIFT in the
corresponding Kconfig file.

* Change in your /etc/syslog.conf or other config file of your favorite
logging program to store kernel logs in async manner. For example,
I added in my rsyslog.conf line "kern.info -/var/log/kernel"
and added "kern.none" in line for /var/log/messages, so I had:
"*.info;kern.none;mail.none;authpriv.none;cron.none /var/log/messages"
/proc/scsi_tgt/help file for list of commands and trace levels. See
also section "Dealing with massive logs" for more info how to make
correct logs when you enabled trace levels producing a lot of logs
data.

Each dev handler has own subdirectory. Most dev handler have only two
files in this subdirectory: "trace_level" and "type". The first one is
Expand Down
35 changes: 32 additions & 3 deletions scst/README_in-tree
Original file line number Diff line number Diff line change
Expand Up @@ -282,7 +282,9 @@ following entries:
BLOCKIO or NULLIO.

- trace_level - allows to enable and disable various tracing
facilities. See content of this file for help how to use it.
facilities. See content of this file for help how to use it. See also
section "Dealing with massive logs" for more info how to make correct
logs when you enabled trace levels producing a lot of logs data.

- version - read-only attribute, which allows to see version of
SCST and enabled optional features.
Expand Down Expand Up @@ -349,7 +351,9 @@ SCST dev handlers can have the following common entries:
handlers).

- trace_level - allows to enable and disable various tracing
facilities. See content of this file for help how to use it.
facilities. See content of this file for help how to use it. See also
section "Dealing with massive logs" for more info how to make correct
logs when you enabled trace levels producing a lot of logs data.

- type - SCSI type of devices served by this dev handler.

Expand Down Expand Up @@ -663,7 +667,9 @@ entries:
of the corresponding devices.

- trace_level - allows to enable and disable various tracing
facilities. See content of this file for help how to use it.
facilities. See content of this file for help how to use it. See also
section "Dealing with massive logs" for more info how to make correct
logs when you enabled trace levels producing a lot of logs data.

- mgmt - main management entry, which allows to add/delete VDISK
devices with the corresponding type.
Expand Down Expand Up @@ -901,6 +907,29 @@ IMPORTANT: Some disk and partition table management utilities don't support
work with files on such file system.


Dealing with massive logs
-------------------------

If you want to enable using "trace_level" file logging levels, which
produce a lot of events, like "debug", to not loose logged events you
should also:

* Increase in .config of your kernel CONFIG_LOG_BUF_SHIFT variable
to much bigger value, then recompile it. For example, value 25 will
provide good protection from logging overflow even under high volume
of logging events. To use it you will need to modify the maximum
allowed value for CONFIG_LOG_BUF_SHIFT in the corresponding Kconfig
file to 25 as well.

* Change in your /etc/syslog.conf or other config file of your favorite
logging program to store kernel logs in async manner. For example,
you can add in rsyslog.conf line "kern.info -/var/log/kernel" and
add "kern.none" in line for /var/log/messages, so the resulting line
would looks like:

"*.info;kern.none;mail.none;authpriv.none;cron.none /var/log/messages"


Persistent Reservations
-----------------------

Expand Down

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