From: Walker, Bruce J <bruce.walker@hp...> - 2003-05-21 23:25:59
Laura recently added a feature such that there is console printf
whenever a process which is trying to migrate fails. The printf
attempts to indicate why the failure happened (Brian explained at least
one of the reasons below).
Note that there are two ways to invoke process migration - manually,
using the migrate command, and automatically by turning on loadleveling
(you must turn it on and any program you want to migrate must be in the
load level list; Laura sent out mail some time ago with the complete
directions, which I think are also part of the tarball).
From: Watson, Brian J.=20
Sent: Wednesday, May 21, 2003 4:06 PM
To: Vladimir Yu. Tereshchenko
Subject: [SSI-devel] Re: [SSI-users] migration
Vladimir Yu. Tereshchenko wrote:
> In documentation at SSI www page I found this:
> 6. IPC
> * all IPC objects/mechanisms are
> * pipes
> * fifos
> * signalling
> * message queues
> * semaphore
> -> * shared memory
> * Unix-domain sockets
> * Internet-domain sockets
This feature list refers to System V shared memory being clusterwide.=20
Another form of shared memory is done via the clone() system call, which
is not clusterwide. This form is used to implement "multi-threaded"=20
processes on Linux, and might be used to share data between Apache's=20
master process and its slaves.
Another potential problem is that clusterwide Unix-domain sockets do not
yet support sending fds between nodes, which Apache might use to pass=20
new connections from the master to one of its slaves. This clusterwide=20
fd passing feature will be added sometime in the future.
If you want to set up a web-serving cluster, I suggest you run a=20
separate copy of Apache on each node and use our integrated version of=20
LVS to load-level connections among them. Aneesh can tell you more about
Hope this helps,
This SF.net email is sponsored by: ObjectStore.
If flattening out C++ or Java code to make your application fit in a
relational database is painful, don't do it! Check out ObjectStore. Now
part of Progress Software. http://www.objectstore.net/sourceforge
ssic-linux-devel mailing list ssic-linux-devel@...