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What are the most common storage options for virtualized Oracle?
This recent presentation (from VMworld 2011) laid out the following storage options for virtualized Oracle database servers (using vSphere):
| Config |
Description |
|---|---|
| Config 1 | ASM using RDM over block storage (FC or iSCSI) |
| Config 2 | ASM using .vmdk files on VMFS over block storage (FC or iSCSI) |
| Config 3 | NFS directly mounted on VM guest OS using Oracle Direct NFS Client |
| Config 4 | ASM using .vmdk files on NFS mounted onto ESX as a datastore |
Config 4 was pretty thoroughly panned as uninteresting. However, the remaining three storage options are all interesting and relatively common. Indeed, a recent EMC Proven Solutions document is entirely about Config 3.
My question is this: In terms of these options, what are folks actually doing? I.e., are you running ASM on RDM? Or are you using VMFS? Likewise are you running over NFS? What results have you gotten? Have you tried various options, and if so, why did you settle on the one you chose? Any input would be very welcome.
LouisLu
161 Posts
0
December 5th, 2011 22:00
Yes. I encountered the same issue on password.
dba_hba
63 Posts
0
December 6th, 2011 05:00
Jeff
If this is not Oracle RAC, and requiring a cluster FS I know of a few companies which still layout their storage on ext3 filesystems over vmdk or RDM. They then enable asynchronous IO using the oracle parameters FILESYSTEMIO_OPTIONS and DISK_ASYNCH_IO to bypass OS cache.
Allan
MacBookPro_9_2
46 Posts
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December 8th, 2011 08:00
Jeff..
I have a customer that is evaluating migrating from RDMs to VMDKs and are considering pros and cons.
Has the storage maximum for RDMs also increased from 2 TB to 64 TB in vSphere 5.0 ?
And how have customers dealt with the issue of Oracle asking customers to move from VMDKs to RDMs, if an Oracle Support issue arises ?
Thanks
-Saty
DarrylBSmith
28 Posts
0
December 8th, 2011 10:00
The number of occurrances of Oracle support asking customers to replicate the problem on a physical server are very rare, 12 to be exact as of about 4 months ago.
As far as the maximum size goes, why would anyone want to use luns > 2TB. This is going to hurt performance significantly. There are several problems with very large luns, > 2TB, and the seriuosness is dependant on many factors, including filesystem type, storage array and OS and can lead to database corruption. Other problems are strickly performance related, such as write pending limits or fewer spindles servicing the workload or artificially randomizing the workload, think pre-fetch performance.
There are many pros and cons for the RDM vs. VMDK comparison.
RDMs will outperform VMDK, slightly.
RDMs allow for array based replication. (snapshots, clones, proxy backup and RDF/replication manager)
VMDKs have better SRM support
VMDKs allow for storage vMotion.
VMDKs allow for DRS with Oracle RAC.
Darryl
MacBookPro_9_2
46 Posts
0
December 8th, 2011 10:00
Thanks for the feedback Darryl..
The tips on RDMs allowing for Array Based Replication are very helpful..
However, does this mean that RDMs don't allow for storage vMotion..
I found this pdf on VMW's site,
http://www.vmware.com/files/pdf/Oracle_Databases_on_vSphere_Deployment_Tips.pdf
And on page 14 it has a table talking about RDMs and VMDKs..
It seems to state that RDMs also allow for vMotion and DRS (but it doesn't explicitly say whether the DRS is with RAC or not)
Thanks again for your feedback
-Saty
DarrylBSmith
28 Posts
0
December 8th, 2011 11:00
vMotion, migrating VMs from one ESX server to another, can be done with RDMs, but only if they are not shared, as in RAC.
Storage vMotion, migrating VMDKs from one datastore to another, does not work with RDMs.
MacBookPro_9_2
46 Posts
0
December 8th, 2011 11:00
Thanks again for clarifying...