I'm looking for peoples experiences with OCFS2 via Oracle Clusterware and OVM.
We are currently looking to use OVM and Oracle Clusterware for one of our production systems and have been experiencing issues in relation to the use of OCFS2 1.4.2.
An example of this is where we want to write a large amount of data to one of the VMs in the cluster. If the node has seen a number of deletions etc...it seems that these deletions do not free up the previously allocated space which leads to insufficient space to write issues.
This is one of a number of issues we've been seeing. I can post further details of the estate if required but I'm looking more for peoples experiences (whether good or bad), expecially in relation to OCFS2.
Can please describe a bit more what you have?
What app use it, underlying disk came from SAN,SAS,SATA,iSCSI remote/local ?
you want to avoid having Lun -> OCFS2 in the OracleVM -> Disk.img -> OCFS2 in the virtual guest
if that's the case, you may want to go to:
Lun -> unused at OracleVM -> phy:// -> OCFS2 in the virtual guest
I have worked in a company where we had a 12 nodes cluster, real boxes having fast storage, and we hit 3 episodes of random reboots / locks.
The fixes were
- available ram .. we run couple of times that system starting to page, and this caused the hung/reboots
- tweak /etc/sysconfig/o2cb timeouts, as defaults one were a bit short
- don't mix speed of storage.
At some point, for backup, we got a storage made of SATA, what was a cheap solution but proven cause issues in this cluster.
what Oracle/cluster version ??
I have successfully used ACFS (a cluster file system that "lives" in an ASM Diskgroup - and is expandable online - think of ASM in this case as a Volume Manager). This works pretty nicely. If used soley as application "files", Oracle in some cases consider this as a CloudFS implementation and will want more $$$ for it. But in my testing chose ACFS over OCFS2.