RAC used filesystem vxfs

[Martin_171]

I want to add the archivelog vg to RAC,the document say that RAC used the raw device,but
archivelog must used filesystem

[Steven E. Protter]

Oracle supports cooked (filesystem) or raw filesystems. Thats pretty universal. You need not be concerned so long as there is enough disk space in the target filesystem.

SEP

[Hein van den Heuvel]

Yes.

Chapter 6 in the "Oracle9 i Real Application Clusters: Administration" manual has several pages dedicated to explaining this.
Check out: RMAN Archiving Configuration Schemes
Notably: Non-CFS Local Archiving Scheme

Indeed RAC requires a (shared) RAW device (or a Cluster File System (Which hp-ux native currently does not offer). In RAW device setup the devices are pretty much fixed in number and size.

Now consider archive logs. They are ever increasing in numbers, and can easily be of varying size (alter system switch logfile). This does not jive with RAW. Thus a filesystem MUST be used.

For instance crash recovery, just the REDO files are needed and those are (required to be) on shared storage. No problemo.

For media recovery, just one node is performing this, and all the archives must be applied, but you have time to make them available to the recovering node. Pick your poisin: Cluster File System (best, but hard to get for hpux), NFS mounts (not bad, over GB local net), ftp (yuck), carrier pigeon, whatever... Just make the files available and off you go.


hth,
Hein.

[Ravi_8]

Hi,

Oracle support both Vxfs and raw file systems. archive log can be on any of these 2.

In my databases it will be always on vxfs

[Hein van den Heuvel]

I beg to differ.

Sep, Oracle RAC puts a twist on things.

Ravi, Archive logs must be on filesystems. I realy don't think it makes sense to even consider raw for those. How would Oracle know how much data is valid in there?

For example:
http://metalink.oracle.com/metalink/plsql/ml2_documents.showFrameDocument?p_database_id=NOT&p_id=37914.1
"Raw Devices and Oracle - 20 Common Questions and Answers"

14. Can I use raw partitions for archive logs? No. Archive logs must be stored on a partition with a UNIX filesystem.

With respect RAC to I saw some oracle notes ('ask tom' ?) recommending a central nfs server. The doc set suggests cross mounted nfs mount points (I dislike those, notably since it does not protect you against node failure without subsequent archive log shipping).

Cheers,
Hein