Bridging Backup Gap
|StorageTeks $50,000 EchoView E400 appliance is a powerful new data protection system that allows IT managers to journal data changes and roll back volumes to a recent stable state in the event of an emergency. The iSCSI-based EchoView E400 has relatively limited data capacity, however, and will be most compelling for midrange servers or groups of entry-level servers.|
PowerQuests V2i Protector
Even with the most stringent backup policy, tape backups protect data up to only the last incremental backup, which oftentimes occurs during the evening. As a result, when there is a need to restore data during the middle of a business day, a significant amount of data may be lost.
The EchoView E400 appliance bridges this gap by continuously monitoring transactions on protected servers, effectively eliminating the risk windowthe period of vulnerability between backups. In the event of a data failure (due to, for example, a virus, application corruption or just plain user error), the EchoView E400 can restore a data volume back to just before data was corrupted.
It is important to note, however, that the EchoView E400 should be considered a tape backup complement and not a replacement for tape.
The EchoView E400, which was released this month, relies on iSCSI, which may be too far out on the bleeding edge for some IT shops. However, based on what eWEEK Labs has seen of this product and on the iSCSI advances we expect in the near future, the EchoView E400 is a very compelling system.
The EchoView E400 supports up to 400GB of data using SCSI hard drives, with ATA versions of the appliance expected later this summer. Company officials said 1- terabyte and 2.4-terabyte versions of the EchoView line of data protection appliances will be released later this year, providing IT managers with more data protection power per appliance.
The data capacity of the EchoView E400 is relatively small, making it a good choice for protecting midrange servers and groups of entry-level servers. In this market space, the only product we have seen with similar capabilities is PowerQuest Corp.s V2i Protector software package. (Look for eWEEK Labs review of the PowerQuest product in a forthcoming issue.)
Larger organizations will be better off using the snapshot and mirroring technology included with their hardware storage controllers.
The EchoView E400 appliance costs $50,000 and supports Solaris 8 and 9 and Windows 2000 Server. Support for other Unix variants, Linux and Windows Server 2003 is planned for a future release.
The concept behind the EchoView is extremely simple and efficient: A device driver is added to the protected servers and monitors transactions written to disks. The driver then "echoes" these transactions simultaneously out to the EchoView E400 appliance.
By staying parallel with the data path (and not in the middle of it), the EchoView E400 can protect data without slowing performance to a crawl or becoming a liability in the event that something happens to the appliance.
An IP-based SAN (storage area network) connects the protected server to the EchoView E400. Given that iSCSI is still very much in its infancy, StorageTek has limited support to clients with QLogic Corp. iSCSI SANblade HBAs (host bus adapters) installed. StorageTek officials said they will add support for other iSCSI HBAs and drivers as iSCSI adoption increases.
The decision to use iSCSI is a good one because it will allow IT managers to leverage their IP networks and place the EchoView E400 far away from their primary servers.
The EchoView E400 stores a replica of the primary data set at the beginning of implementation. As data is created, the EchoView E400 catches the echoes from the device driver and writes them into a journaling volume history.
The journaling volume history is an important and extremely flexible feature that allowed us to roll back changes to a specific point in time. For example, after intentionally corrupting a file on our server, we went back to the journaling volume history to restore a valid version of the file.
The EchoView E400 uses volume virtualization technology to mount a view of the journaling volume history using iSCSI. It was from this virtual volume that we were able to grab a previous version of the file and restore it to our primary storage unit.
The EchoView E400 automatically time-stamps views on the volume history, but we were also able to explicitly create and label views at points in which we knew the server was stable. This feature will also be helpful in testing new patches and applications, allowing administrators to roll back changes in the event that something goes wrong.
The EchoView E400 offers two types of rollback operations: a full rollback, for times when all the contents of a data volume have been destroyed, and a differential rollback, for restoring servers back to a stable state.
The management controls of the EchoView are split into two distinct interfaces: a client-side GUI that resides on the protected servers and a Web-based management utility that is used by the primary storage or backup administrator.
The reason for the split in utilities is to provide administrative granularity. It would be easy to have a single management screen, but this would give storage administrators too much power, allowing them to see into volumes they would normally not have permission to view.
Senior Analyst Henry Baltazar can be reached at email@example.com.