Specifications

LifeKeeper Operations
IPC
Semaphores
and IPC
Shared
Memory
LifeKeeper requires Inter-Process Communication (IPC) semaphores and IPC
shared memory. The default Red Hat values for the following Linux kernel options
are located in/usr/src/linux/include/linux/sem.hand should be sufficient to support
most LifeKeeper configurations.
Option Required Default Red Hat 6.2
SEMOPM14 32
SEMUME20 32
SEMMNU60 32000
SEMMAP25 32000
SEMMNI25 128
System File
Table
LifeKeeper requires that system resources be available in order to failover
successfully to a backup system. For example, if the system file table is full,
LifeKeeper may be unable to start new processes and perform a recovery. In
kernels with enterprise patches, including those supported by LifeKeeper, file-max,
the maximum number of open files in the system, is configured by default to 1/10 of
the system memory size, which should be sufficient to support most LifeKeeper
configurations. Configuring the file-max value lower than the default could result in
unexpected LifeKeeper failures.
The value of file-max may be obtained using the following command:
cat /proc/sys/fs/file-nr
This will return three numbers. The first represents the high watermark of file table
entries (i.e. the maximum the system has seen so far); the second represents the
current number of file table entries, and the third is the file-max value.
To adjust file-max, add (or alter) the “fs,file-max” value in /etc/sysctl.conf (see
sysctl.conf(5) for the format) and then run
sysctl –p
to update the system. The value in /etc/sysctl.conf will persist across reboots.
LifeKeeper Operations
Item Description
Kernel
Debugg
er (kdb)
init s
Before using the Kernel Debugger (kdb) or moving toinit son a LifeKeeper protected
server, you should first either shut down LifeKeeper on that server or switch any
LifeKeeper protected resources over to the backup server. Use ofkdbwith the
LifeKeeper SCSI Reservation Daemons (lkscsidandlkccissd) enabled (they are
enabled by default) can also lead to unexpected panics.
214User Guide