Well - not 'any time' - as I only write to the disk at specific times. Maybe I should do a "sync" on the RW side and schedule a remount on the RO side afterwards.
best regards/Med vennlig hilsen Roger Evans Systemkonsulent ________________________________________________________________________ On Wed, 2011-10-12 at 10:15 +0200, Agblad Tore wrote: > The server that has it in rw mode can write new data at any time. > Thus reorganize datablocks inodes and whatever needed to fit the new files > into free space. > The other server may not be aware of this move of bytes on the disk. > So an IO error might happen, or maybe read-error, don't know which. > > _________________________________________________ > Tore Agblad > System programmer, Volvo IT certified IT Architect > Volvo Information Technology > Infrastructure Mainframe Design & Development, Linux servers > Dept 4352 DA1S > SE-405 08, Gothenburg Sweden > Telephone: +46-31-3233569 > E-mail: [email protected] > http://www.volvo.com/volvoit/global/en-gb/ > > > -----Original Message----- > From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Roger > Evans > Sent: den 12 oktober 2011 09:44 > To: [email protected] > Subject: Re: dasd_configure doesn't see partition 1 on RO disk > > I've been using this scenario for database backups since we had the > discussion about shared VM disks on this thread about a year ago. > David made the point then that if you had a hipervisor that allowed it, > not making a disk dependent on one of the machines being up at all times > (as with NFS), had some advantages.. I also used Tore's suggestion to > stick to ext2 so nobody would try to replay a journal. .I use them > for database backups that I take each night, and for SLES10 (both SP1 > and SP3) it works fine. IF the RW linux is down (usually because it > didn't come up again), caching won't be an issue. > > If the machine that 'owns' the database/disk is down, I can still see > the database, and can recover a copy on the machine that has RO access. > without having to go in and change the VM configuration. It's also easy > to > check to see that the backup went ok. and the recovery would work. > > I haven't tried sharing a disk between 2 SLES 11 machines yet, and > that's where I'm going with upgrades. If it doesn't work, it would be > nice to know. Why would the fact that one of the machines has the disk > mounted RW > keep the other(s) from seeing it at all? > > Best Regards/ > Med vennlig hilsen > > Roger Evans > > > > ________________________________________________________________________ > > > > On Tue, 2011-10-11 at 10:11 -0600, Mark Post wrote: > > > >>> On 10/11/2011 at 04:26 AM, Roger Evans <[email protected]> wrote: > > > I am trying to mount a disk R/O from two linux machines on one VM. One > > > of them is SLES10 where the disk is defined in zipl.conf. The other > > > is a new SLES11 ('CLPRODB2).. > > > > > > The disk is mounted RW on a SLES10sp3 machine. > > > > This is never a good idea. If you want to share a disk between z/VM > > guests, _all_ of them need to have it read only. None of them can have it > > read-write. There's too many layers of caching going on for it to work > > reliably, if at all. > > > > If you absolutely have to have access to a disk that is mounted read-write, > > use NFS to export it read only. > > > > > > Mark Post > > > > ---------------------------------------------------------------------- > > For LINUX-390 subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO LINUX-390 or > > visit > > http://www.marist.edu/htbin/wlvindex?LINUX-390 > > ---------------------------------------------------------------------- > > For more information on Linux on System z, visit > > http://wiki.linuxvm.org/ > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit > http://wiki.linuxvm.org/ > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit > http://wiki.linuxvm.org/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
