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By Henry Baltazar  |  Posted 2005-11-07 Email Print this article Print
 
 
 
 
 
 
 


With tighter application integration now on board, Kashya Inc.s updated KBX5000 appliance moves from block-level data replication to the realm of continuous protection.

The KBX5000 requires a substantial upfront investment, but eWEEK Labs tests show that the appliance enables continuous protection and fast recovery when IT managers must not only make sure data is replicated over long distances but also be able to speedily relaunch applications and services at remote sites.

How is WAN replication aiding in business continuity? Click here to read more.
The KBX5000, which shipped last month, is more application-friendly than its predecessors. However, at its core its still a Fibre Channel SAN (storage area network) extension tool, so its not a good choice for environments that have a lot of DAS (direct-attached storage) or iSCSI.

Kashya offers a standard replication solution (two KBX5000 units) starting at $65,000. An HA (high availability) package, where two KBX5000 units are clustered at two sites, is priced at $95,000.

We tested a KBX5000 implementation with replication and CDP (continuous data protection) capabilities, priced at $100,000 for two appliances or $130,000 for the HA implementation.

IT managers who want the KBX5000 appliances CDP functions without WAN replication can purchase a single unit for $50,000.

Installation of the KBX5000 is largely unchanged from previous versions of the appliance weve tested. Once plugged into the SAN, the KBX5000 quickly detected the storage units on our test SAN and allowed us to configure them for replication.

As with all SAN products, the KBX5000 detects storage units using WWNs (World Wide Names). Because WWNs are particularly difficult to remember, we recommend that IT managers document WWNs and their corresponding storage arrays before beginning the installation.

Kashya still requires a filter driver to attach hosts to the KBX5000—a bit of a negative for most IT managers. The driver duplicates write transactions, ensuring that changes are sent to the primary storage device and to the KBX5000 for replication.

IT managers running Cisco Systems Inc. SAN switches, however, can use the SANTap feature in place of the Kashya filter driver. As Kashya forges alliances with more SAN switch vendors, the need for the filter driver will disappear, but that could take a few more years.

After identifying our host (the unit being replicated) and target (the unit receiving replication updates over the WAN) using Kashyas management interface, it was easy to set up our replication policies.

The KBX5000 appliances new CDP capabilities give IT managers more granular control over how applications are restored. For example, in previous versions of the product, administrators could restore a volume to a specific time using a snapshot. But because this method lacked application quiescing and consistency checks, the snapshot could wind up having incorrect memory allocation or inconsistent logs—which could complicate and slow application recovery. The KBX5000 now works with Microsoft Corp.s VSS (Windows Server 2003 Volume Shadow Copy Service) to ensure that applications are quiesced before snapshots are taken, ensuring clean server recoveries.

The updated KBX5000 also can look at server activity and roll back storage volumes at the database row or transaction level, rather than at block level only. The appliance uses an API that communicates with Oracle Corp.s Hot Backup API to get application-level information for recovery operations for Oracle databases. For Microsoft SQL Server, the appliance uses an API that communicates with Microsofts Virtual Device Interface to get the information.

Next page: Evaluation Shortlist: Related Products.



 
 
 
 
 
 
 
 
 
 
 

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