Bug #14281 | MySQL server 4.1.12 Fails to start on a NFS mounted directory in HP-UX platform | ||
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Submitted: | 25 Oct 2005 6:47 | Modified: | 25 Oct 2005 12:23 |
Reporter: | tejaswi gk | Email Updates: | |
Status: | Not a Bug | Impact on me: | |
Category: | MySQL Server | Severity: | S1 (Critical) |
Version: | 4.1.12 | OS: | HP/UX (HP-UX) |
Assigned to: | CPU Architecture: | Any |
[25 Oct 2005 6:47]
tejaswi gk
[25 Oct 2005 12:23]
Valeriy Kravchuk
Thank you for a problem report. But it really not a bug, but a problem you should avoid, especially when using InnoDB tables. According to the manual (http://dev.mysql.com/doc/refman/4.1/en/multiple-servers.html): "Warning: Normally you should never have two servers that update data in the same databases. This may lead to unpleasant surprises if your operating system does not support fault-free system locking. If (despite this warning) you run multiple servers using the same data directory and they have logging enabled, you must use the appropriate options to specify log filenames that are unique to each server. Otherwise, the servers try to log to the same files. Please note that this kind of setup only works with ISAM, MyISAM and MERGE tables, and not with any of the other storage engines. The warning against sharing a data directory among servers also applies in an NFS environment. Allowing multiple MySQL servers to access a common data directory over NFS is a very bad idea. * The main problem is that NFS is the speed bottleneck. It is not meant for such use. * Another risk with NFS is that you must devise a way to ensure that two or more servers do not interfere with each other. Usually NFS file locking is handled by the lockd daemon, but at the moment there is no platform that performs locking 100% reliably in every situation. Make it easy for yourself: Forget about sharing a data directory among servers over NFS. A better solution is to have one computer that contains several CPUs and use an operating system that handles threads efficiently." So, the fact that this setup shoud not work for InnoDB is clearly documented.
[25 Oct 2005 18:20]
James Day
See the no_auth_nlm option described in section E of the NFS FAQ at http://nfs.sourceforge.net/ . This looks like a known NFS issue rather than a MySQL issue with either single or multiple servers running.