2009.8.6 SOL10328: Forcing a file system check on the next system reboot

SOL10328: Forcing a file system check on the next system reboot

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Updated: 7/23/09 7:43 AM

The fsck utility is used to scan the file system for errors, and to correct those errors if possible. In order to correct errors, the file systems must be unmounted. Performing a file system check using the fsck utility can be a tedious manual process requiring the user to reboot the system to a minimal run level and then issue an fsck on each file system listed in the /etc/mtab file. This method requires direct access to the system in order to access and run the fsck utility.

A more convenient method is to force a file system check on the next system reboot. This method removes the tedious manual process, and allows the system to check all of the available file systems.

Important: F5 Networks recommends that you have direct access to the system during a forcefsck so that you are able to observe any errors or information that may be reported during the fsck process. While this method removes the manual process of specifying the various file systems, the system reboots into a minimal run level to perform the necessary tasks.

The following two methods can be used to force a file system check on the next reboot:

• Creating a forcefsck file in the root directory

  This method allows you to schedule a file system check at the next reboot by creating a blank file called forcefsck that resides in the / directory. When the system is rebooted, it will read this file and begin checking the file systems.

• Forcing a file system check using the shutdown command

  This method allows you to reboot the system immediately and perform a forced file system check using the shutdown command. When the command is issued, the system reboots and begins checking the file systems.

Creating a forcefsck file in the root directory

To create a forcefsck file in the root directory, perform the following procedure:

1. Log in to the command line.
2. To create the forcefsck file, type the following command:
   

   touch /forcefsck

3. Leave the file in place. A file system check is automatically run the next time the system reboots.

Forcing a file system check using the shutdown command

1. Log in to the command line.
2. To restart the BIG-IP and force a file system check, type the following command:
   shutdown -rF now

Once the fsck has finished checking the file systems, the system will continue to boot normally into the proper run levels.

2009.8.6 SOL7036: The Linux uptime counter wraps after 497 days

SOL7036: The Linux uptime counter wraps after 497 days

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Known Issue
Updated: 7/21/09 11:05 AM

This is the result of a known issue, which was discovered in 1998 and still exists in the Linux 2.4 kernel. The kernel computes the system uptime based on the internal jiffies counter, which counts the time since boot in units of 10 milliseconds, or jiffies. The counter is a 32-bit counter, which has a maximum value of 2^32, or 4,294,967,296. When the counter reaches this value (after 497 days, 2 hours, 27 minutes, and 53 seconds, or approximately 16 months), it wraps back around to zero and continues to increment.

F5 Networks Product Development is tracking this Linux issue as CR74550. Currently, no Linux kernel patch is available to resolve this issue.

When the counter wraps, the following side effects may be observed:

• The ps (Process Status) command may report incorrect TIME values for daemons that were running at the time of the counter wrap
• Some processes that depend on accurate elapsed time calculations may be adversely affected, as detailed in the following Solutions:

SOL7071: SCCP kernel driver i2c read failure

SOL8087: SCCP kernel driver timer wrap may cause system component health misreadings (FirePass only)

SOL9679: The lacpd daemon stops sending LACP messages after 497 day linux uptime wraparound

SOL9683: The gtmd, tmm, or bcm56xxd daemons may crash after 497 day linux uptime wraparound

SOL10311: The performance graphs no longer display data after 497 day linux uptime wraparound

Note: These are the only known side effects of the uptime counter wrapping. The issues documented in these Solutions have been patched as noted therein. If you encounter issues that seem related but are not documented here, contact F5 Networks Technical Support.

Workaround

You can work around most issues created by the wrapping of the uptime counter by rebooting the system. In some cases, further remedial steps may be necessary. Refer to the solutions above for specifics.

You can avoid this issue by rebooting the system prior to the 497 day counter wrap. To determine how long the system has been up, use the Linux uptime command. The uptime command produces output that appears similar to the following example:

19:52:48 up 20 days, 9:24, 1 user, load average: 0.09, 0.05, 0.11

2009.8.6 Cat 3750 Stack function

2009.8.6 Cat 3750 Stack function
Cat 3750在有Stack功能之下的升級方式,請參閱Catalyst 3750 Software Upgrade in a Stack Configuration with Use of the Command-Line Interface
Cat3750設定Stack功能方式:Managing Switch Stacks or Creation and Management of Catalyst 3750 Switch Stacks
Cat3750當有cross-stack功能在時,要如何設定EtherChannel,請看Cross-Stack EtherChannel on a Catalyst 3750 Switch Configuration Example

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