Re: mount -u effects
nice and quick point! thanks a lot :) You could have found it out by refering to man mount. :-) yes, it seems to be right! ;) So I'd say you should always take care that write operations are finished properly (and so brought to an end) but, how to become sure my write operations are completely finished?? by obtaining some sort of sleep time before my restart command in my upgrade shell for example? or there are other special ways to do so? Best Regards, t.a.k On Tue, Dec 11, 2012 at 11:13 AM, Polytropon free...@edvax.de wrote: On Tue, 11 Dec 2012 10:55:10 +0330, takCoder wrote: via googling, i found out that i can use mount -u on the mentioned device, and then after doing whatsoever needed, when i restart my server the ro permission will be back via applying old fstab.. You could have found it out by refering to man mount. :-) but i have no idea what kind of effects it may have on my server.. i couldn't find anything but suggestions about not to use this so often.. and i really need to know why?? cause my bsd server is not allowed to be missed almost at all.. i think that because this -u option is just increasing my permissions in this case, there won't be a danger for my server. is that true?! There are _few_ side effects that _may_ apply when using the -u option. From the manual: The -u flag indicates that the status of an already mounted file system should be changed. Any of the options discussed above (the -o option) may be changed; also a file system can be changed from read-only to read-write or vice versa. An attempt to change from read-write to read-only will fail if any files on the file system are currently open for writing unless the -f flag is also specified. The set of options is determined by applying the options specified in the argument to -o and finally applying the -r or -w option. So I'd say you should always take care that write operations are finished properly (and so brought to an end). -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: mount -u effects
On Tue, 11 Dec 2012 11:39:24 +0330, takCoder wrote: but, how to become sure my write operations are completely finished?? by obtaining some sort of sleep time before my restart command in my upgrade shell for example? or there are other special ways to do so? Basically, no user action is needed. If you perform an umount (or change back to -o ro), all remaining buffers will be flushed, so writes are eventually performed at this time. If such an operation hasn't been finished yet, mount will complain, and you have some time to wait and try again. :-) In case you're using -f (force), this specific check will not be performed, so it shouldn't be used. Similarly, the sync command will cause all buffers to be flushed. The file system driver will then let the device driver perform the operation, which should be finished in finite time (usually below a second). See man sync for details. You could always use the lsof command to check if there are still files open for writing on the respective file system. At the time you're getting your command prompt back, the write operation is likely to be finished. Add some time typing the mount command, and you should be fine. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: mount -u effects
On Tue, 11 Dec 2012 10:55:10 +0330, takCoder wrote: via googling, i found out that i can use mount -u on the mentioned device, and then after doing whatsoever needed, when i restart my server the ro permission will be back via applying old fstab.. You could have found it out by refering to man mount. :-) but i have no idea what kind of effects it may have on my server.. i couldn't find anything but suggestions about not to use this so often.. and i really need to know why?? cause my bsd server is not allowed to be missed almost at all.. i think that because this -u option is just increasing my permissions in this case, there won't be a danger for my server. is that true?! There are _few_ side effects that _may_ apply when using the -u option. From the manual: The -u flag indicates that the status of an already mounted file system should be changed. Any of the options discussed above (the -o option) may be changed; also a file system can be changed from read-only to read-write or vice versa. An attempt to change from read-write to read-only will fail if any files on the file system are currently open for writing unless the -f flag is also specified. The set of options is determined by applying the options specified in the argument to -o and finally applying the -r or -w option. So I'd say you should always take care that write operations are finished properly (and so brought to an end). -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
