HP solution for Database's data fault tolerance

[Delrish]

Hello,

As you know HA clustering offers hardware, OS, and software fault tolerance and both MS SQL and Oracle support them. However what about data fault tolerance. Is there any solution to write data on two seprated disk arrays? I know what the replication is.However I want to use two MSA 1000 and write data on both of them in realtime.is it possible?How?

Alireza

[melvyn burnard]

Well you could use MirorDisk/UX to mirror the arrays.
What about the application vendor? Oracle has a product for replicating the database (Oracle Standby Database I think) from one server to another, so that would get the data written onto the second MSA.
Sybase also do a data replication server software to acheive the same thibg.

[Delrish]

Thank you,

But I want to use a server with two MSA 1000. The server should write DATA on both of the Arrays, or something like it. I do not add an extra server and connect it to second array and using replication between two databases.

[Patrick Wallek]

If you set up your VG so it contains LUNs from both MSA's, then create the LVOL so that they are mirrored between the MSA's.

The MirrorDisk/UX software will keep the LUNs on each MSA in sync.

[melvyn burnard]

then MirrorDisk/UX would be the way to go.
When you set up the arrays, create duplciate LUN's, and then use these LUN's to set up your VGs and LV's, then mirror from one array to the other.

[Rita C Workman]

For local, as was said, MirrorDisk/UX.

For remote replication, HP offers CA (Continuace Access) and EMC offers SRDF. Other vendors have their versions too.
But with this kind of mirroring your into DR technology.

Rgrds,
Rita

[Delrish]

Thank you All,

What about Oracle RAC systems?Is there way for it too?

Alireza

[Yogeeraj_1]

hi,

Note that with RAC, you are not really involved in the physically design when scaling up.

see:
http://download-west.oracle.com/docs/cd/B10501_01/rac.920/a96597/toc.htm

It should not be confused with Oracle Parallel server. RAC is a new more robust OPS.

Also, read about the way in which cache fusion works.
see
http://download-west.oracle.com/docs/cd/A91202_01/901_doc/rac.901/a89867/whatsnew.htm#983402

Below a quote that should clarify what a RAC provides: (http://www.oracle.com/technology/pub/articles/hunter_rac10g.html#2)

Oracle RAC, introduced with Oracle9i, is the successor to Oracle Parallel Server (OPS). RAC allows multiple instances to access the same database (storage) simultaneously. It provides fault tolerance, load balancing, and performance benefits by allowing the system to scale out, and at the same timeâ because all nodes access the same databaseâ the failure of one instance will not cause the loss of access to the database.

At the heart of Oracle RAC is a shared disk subsystem. All nodes in the cluster must be able to access all of the data, redo log files, control files and parameter files for all nodes in the cluster. The data disks must be globally available to allow all nodes to access the database. Each node has its own redo log and control files but the other nodes must be able to access them in order to recover that node in the event of a system failure.

One of the bigger differences between Oracle RAC and OPS is the presence of Cache Fusion technology. In OPS, a request for data between nodes required the data to be written to disk first, and then the requesting node could read that data. In RAC, data is passed along with locks.

Not all clustering solutions use shared storage. Some vendors use an approach known as a federated cluster, in which data is spread across several machines rather than shared by all. With Oracle RAC 10g, however, multiple nodes use the same set of disks for storing data. With Oracle RAC, the data files, redo log files, control files, and archived log files reside on shared storage on raw-disk devices, a NAS, a SAN, ASM, or on a clustered file system. Oracle's approach to clustering leverages the collective processing power of all the nodes in the cluster and at the same time provides failover security.



hope this helps too!

regards
yogeeraj

[Delrish]

Thank you Yogeeraj,

However,The problem is another thing. A RAC system provides OS,Hardware,Software fault tolerance but it does not do anything for data fault tolerance ( you should use shared storage and most of them use raid technology) but I want have a realtime copy of all the data on another disk arry. I mean, I use a MSA1000 as a shared storage for RAC and using another MSA1000 for real time mirroring the first MSA on second one. DO you have any Idea?

Alireza

[Yogeeraj_1]

hi,

not too sure if you can do it with the MSA. Can you check at the HP Storage works level?

I know that for the HP EVA series, there is the Continuous Access EVA solution which is a storage-based application that performs replication between HP StorageWorks Enterprise Virtual Arrays. It utilizes HPâ s leading edge technologies to perform point-in-time local replication, highly available Fibre Channel (FC) multi-path support, dual FC fabric, nearline data protector and campus, metro or continental SAN extensions.

regards
yogeeraj