Messages in this thread | | | From | Rainer Krienke <> | Subject | 2.4.17: Hardwired limit of parallel nfs mounts | Date | Tue, 15 Jan 2002 15:49:22 +0100 |
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Hello to everyone,
I have a question regarding the maximal number of NFS-mounts in Kernel 2.4.17 (on a i686 box running suse7.3). I found out that this number is hardwired in the kernel in linux/fs/super.c in the bitmap unnamed_dev_in_use. Since we have put all the data of our users (~4000) on several central NFS servers it happens sometimes that eg. the mailserver (running linux) has to mount several hundred home directories by autofs e.g. when users are reading Mail by POP/IMAP. In this sense the limit of 256 is quite small. Even when I set the expiration time of autofs to a quite small value it happens sometimes that autfs cannot mount home directories since the mtable is currently full (errno: EINVAL).
To change the limit I simply replaced the limit of 256 by 1024 in super.c. In this situation I can mount about 800 NFS-directories at the same time and then the kernel complains in /var/log/messages: .... automount[861]: attempting to mount entry /home/anotheruser Jan 15 09:03:11 bris kernel: RPC: Can't bind to reserved port (98). Jan 15 09:03:11 bris kernel: NFS: cannot create RPC transport. Jan 15 09:03:11 bris kernel: nfs warning: mount version older than kernel Jan 15 09:03:11 bris kernel: RPC: Can't bind to reserved port (98). Jan 15 09:03:11 bris kernel: NFS: cannot create RPC transport.
Nothing serious happens, exept that I cannot mount more NFS-Dirs until autofs has expired some of the ones previously mounted. Does anyone know why this happens? Do I have to change anything else of the kernel to allow a number of about 1024 NFS-mounts at the same time?
Wouldnt it be generally a good idea to raise this limit or to make the value configurable in any way? Why does this limit still exist anyway?
Thanks to all Rainer -- --------------------------------------------------------------------- Rainer Krienke krienke@uni-koblenz.de Universitaet Koblenz, http://www.uni-koblenz.de/~krienke Rechenzentrum, Voice: +49 261 287 - 1312 Rheinau 1, 56075 Koblenz, Germany Fax: +49 261 287 - 1001312 --------------------------------------------------------------------- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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