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Ontape to Disk

Posted in 2009

Summary

A DBA on IFMX 11.50FC3 / Solaris 10 (Intel) backed up a ~1.6 TB database to disk using ontape with TAPEDEV set to STDIO, and asked whether restores of images over 1 TB are known to fail. Replies said no specific size limit should apply since with STDIO ontape just reads until the stream ends, so the real constraint is the OS/filesystem's large-file support and having enough contiguous space (ideally on a separate volume). Suggestions: verify the backup image with archecker, test the procedure on a smaller database, and pipe through compress/gzip to cut disk usage. No confirmed outcome of an actual 2 TB restore is recorded.

Auto-generated by DrWatson from the posts below — may be imperfect; read the full thread.

Topics: Backup & Restore, Server Administration

kathy.duchene@state.mn.us — — source: Usenet: comp.databases.informix

I set the onconfig parameter TAPEDEV to STDIO and backed up a 2 terabyte database to disk. I have been told that restoring a database over 1 terabyte from disk may not work. Has anyone encountered or heard of specific issues related to restoring a 2 terabyte database from disk?

↪ replying to kathy.duchene@state.mn.us
theBP — — source: Usenet: comp.databases.informix

kathy.duchene@state.mn.us wrote: > I set the onconfig parameter TAPEDEV to STDIO and backed up a 2 > terabyte database to disk. I have been told that restoring a database > over 1 terabyte from disk may not work. Has anyone encountered or > heard of specific issues related to restoring a 2 terabyte database > from disk? Version? Platform? Any limitations on the disk as regards filesystem?

↪ replying to kathy.duchene@state.mn.us
Fernando Nunes — — source: Usenet: comp.databases.informix

kathy.duchene@state.mn.us wrote: > I set the onconfig parameter TAPEDEV to STDIO and backed up a 2 > terabyte database to disk. I have been told that restoring a database > over 1 terabyte from disk may not work. Has anyone encountered or > heard of specific issues related to restoring a 2 terabyte database > from disk? I suppose not many people have tried that (ontape doesn't work in parallel)... Someone may have comments on the limits (assuming there is one), but meanwhile you could try to verify the backup image using archecker... It will probably take a lot of time but it should not need too much disk space (a few tens of MB probably). You can find the information about archecker in your Backup and Restore Guide. If I had 2-3TB I could make a test, but I don't... Note however that if you're using STDIO, than ontape doesn't really care about the size of the data... It should keep reading it until it ends... If you have the file on disk I'd bet it's ok... But I maybe missing something... So, the question may be at another level (OS for example). Do your OS work well with files of this size? Probably yes. Regards. -- Fernando Nunes Portugal http://informix-technology.blogspot.com My email works... but I don't check it frequently...

↪ replying to theBP
kathy.duchene@state.mn.us — — source: Usenet: comp.databases.informix

On Mar 12, 10:36 am, theBP <th...@Usenet-News.Net> wrote: > kathy.duch...@state.mn.us wrote: > > I set the onconfig parameter TAPEDEV to STDIO and backed up a 2 > > terabyte database to disk.  I have been told that restoring a database > > over 1 terabyte from disk may not work.  Has anyone encountered or > > heard of specific issues related to restoring a 2 terabyte database > > from disk? > > Version? > Platform? > Any limitations on the disk as regards filesystem? Informix 11.50FC3, Solaris 10, Intel. The database is approx. 1.6 terabytes and the disk space is set up for 2 terabytes

↪ replying to kathy.duchene@state.mn.us
Ian Michael Gumby — — source: Usenet: comp.databases.informix

On Mar 12, 12:31 pm, kathy.duch...@state.mn.us wrote: > On Mar 12, 10:36 am, theBP <th...@Usenet-News.Net> wrote: > > > kathy.duch...@state.mn.us wrote: > > > I set the onconfig parameter TAPEDEV to STDIO and backed up a 2 > > > terabyte database to disk.  I have been told that restoring a database > > > over 1 terabyte from disk may not work.  Has anyone encountered or > > > heard of specific issues related to restoring a 2 terabyte database > > > from disk? > > > Version? > > Platform? > > Any limitations on the disk as regards filesystem? > > Informix 11.50FC3, Solaris 10, Intel.  The database is approx. 1.6 > terabytes and the disk space is set up for 2 terabytes Interesting. On Solaris 10, Intel, you should be able to do this. I have to urge caution because of the size of the database and I haven't created a single file that large. If you have a contiguous space of 2 TB, you can do this, however you may want to work from a different file system so your other files don't take up space on this volume. If you can, work from a different volume that is not physically part of this volume. If your volume is on a SAN and you can mount this file system via NFS to a different machine, you could in theory try to restore the database, provided you have the same configuration. Is it possible to try this on a smaller database?

↪ replying to kathy.duchene@state.mn.us
TheBigPotatoe@Nothere.Co.Uk — — source: Usenet: comp.databases.informix

On Mar 12, 5:31 pm, kathy.duch...@state.mn.us wrote: > On Mar 12, 10:36 am, theBP <th...@Usenet-News.Net> wrote: > > > kathy.duch...@state.mn.us wrote: > > > I set the onconfig parameter TAPEDEV to STDIO and backed up a 2 > > > terabyte database to disk.  I have been told that restoring a database > > > over 1 terabyte from disk may not work.  Has anyone encountered or > > > heard of specific issues related to restoring a 2 terabyte database > > > from disk? > > > Version? > > Platform? > > Any limitations on the disk as regards filesystem? > > Informix 11.50FC3, Solaris 10, Intel.  The database is approx. 1.6 > terabytes and the disk space is set up for 2 terabytes You could of course pipe it to gzip | gunzip or compress | uncompress and reduce space used on the filesystem quite considerably

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