Network administrators looking to back up and replicate data collected on a variety of servers with a minimum of overhead should evaluate Veritas Software Corp.'s Storage Replicator for NT 2.0. However, this release has several significant shortcomings, and Veritas has made it difficult for users of SRNT's predecessor line, Replication Exec, to upgrade.
Released last month at a price of $3,995 for two server licenses and an additional $1,995 per server, SRNT 2.0 is the successor to Veritas' powerful Replication Exec 1.5 and 1.5.1. eWeek Labs found the new product stable, scalable and effective, and we believe it consolidates backup chores well.
However, Version 2.0 has some significant shortcomings, and we recommend that administrators wait for the next release of the product, due in November, before making the jump. We eagerly await the next release because it will be the best server backup solution on the market--if it includes all the features that Veritas officials say it will.
For now, though, we hesitate even to recommend that users of Replication Exec upgrade to SRNT 2.0 because Veritas has made upgrading costly and cumbersome. SRNT 2.0's design is much better than that of Replication Exec, but it is also so different that the new product is not backward-compatible. Migration requires uninstalling Replication Exec, and Veritas does not offer an upgrade discount.
SRNT 2.0 is compatible with Windows NT 3.51 or Windows 4.0 with Service Pack 5 but does not support Windows 2000.
Other replication and backup solutions on the market, such as Legato Systems Inc.'s Octopus 4.0 for Microsoft Windows NT/2000 and Computer Associates International Inc.'s ARCserve 2000, provide many of the same features as SRNT but at a significantly higher price. ARCserve 2000 supports heterogeneous clients, including Linux, Windows 9x and NetWare, with virus scanning capability at a cost of $1,395 for the ARCserve 2000 Advanced edition. However, the integrated virus scanning functionality in ARCserve 2000 slows performance, and the total deployment cost exceeds that for SRNT 2.0 when agent prices are included. Octopus 4.0 for Microsoft Windows NT/2000 supports Microsoft Corp.'s Clustering Services but is priced at $4,998 for a two-server license and $2,499 for each additional server license.
The most significant shortcoming in SRNT 2.0 is the lack of support for Microsoft's Clustering Services. That product provides an effective failover methodology that keeps an operation such as a server farm humming at full speed at all times. If Veritas' new product supported Microsoft's Clustering Services, it could provide uninterrupted data access, even with catastrophic server failures within clusters. Lacking that support, though, it would fail to synchronize with backup servers unless a job was manually scheduled to do so. Veritas officials told eWeek Labs that the next release of SRNT will support Microsoft's Clustering Services and include an RMS (replication management server) failover capability.
Another limitation in SRNT 2.0 is a lack of virus scanning. However, the product's excellent design would make virus scanning simple. Again, Veritas officials said the next release will include virus scanning. The absence of a distributed virus scanning scheme improves SRNT 2.0's speed and reduces overhead.
Although Veritas seems to be one release away from producing a real winner, SRNT 2.0 is a very promising product with lots of significant improvements over Replication Exec. Veritas has added new wizards and a new GUI that can control all of the product's functions. (All functions can also be controlled from a command line.) The wizards make the job of scheduling backup tasks much less cryptic than it is with Replication Exec and many rival tools.
SRNT's monitoring tools are also much improved over those in Replication Exec. The console provides a very readable display of backup and replication jobs, making it easy to tell the status of each and spot problems.
The product also has a new autodiscovery function that enables every SRNT-equipped server to detect the RMS with which it will exchange data. However, managers must ensure that the RMS for a domain is up and running whenever they deploy SRNT on another server because SRNT can accidentally allow the user to configure a server as the RMS, setting the stage for system crashes.
SRNT 2.0 is also highly scalable. It can coordinate replication among as many as 1,000 nodes, but our tests indicate that any company using it on more than 50 servers will need considerable in-house expertise.
In tests, we were impressed with SRNT's innovative design, which stores transitory data in "journals" on each server. Also, all backup activity occurs exclusively between the RMS and a tape system, meaning that production servers are freed from CPU-intensive backup jobs. These design features can greatly reduce the overhead associated with data replication.
SRNT also supports traditional backup methods, such as scheduling, script execution, and incremental or exact data replication.
Veritas' product performed flawlessly in real-time replication jobs of one-to-one and one-to-many for content distribution and many-to-one for data consolidation. However, we detected a bug that could cause system crashes; if a server involved in a replication task is called into a second replication task before the first one is complete, the RMS crashes. Terminating the second job allowed the primary real-time replication job to resume and finish successfully. As long as replication tasks are scheduled to avoid simultaneous tasks involving one server, the system will be highly stable. But it would be easy for a manager to schedule tasks to overlap. Company officials told us they will fix the bug in the next release; we believe they should provide a patch in the meantime.
We also interrupted replications by disturbing the network and observed that after the connection was reestablished, SRNT, utilizing its journaling methods, picked up right where it left off and completed the job.
All data consolidation or content distribution jobs can be configured to use no more than a specified amount of network bandwidth, but they cannot be fine-tuned to use only a given share of available bandwidth at any given time.
SRNT does not use encryption or virus scanning, so it puts less burden on CPUs and bandwidth than rival products do. Veritas officials said they plan to leverage their journaling technology in future releases to perform virus scanning within quarantined zones on target machines. Veritas officials also said that future releases will integrate rollback functionality that will enable administrators to reset content back to any time frame supported in the software, allowing a historical view of any data.
SRNT, while capable of reading both File Allocation Table and NTFS (NT File System) file formats and maintaining write-order fidelity to ensure smooth data recovery, only replicates to NTFS volumes. SRNT also provides a fine level of control over jobs allowing Disk, Volume, Directory, File (open and closed), and Block replication. Registry replication options are planned for future releases.
Technical Analyst Manish Parks can be contacted at firstname.lastname@example.org.
|eWeek Labs // Storage Replicator 2.0 for Windows NT|
Network administrators working with systems, such as Web server farms, that require constant replication, distribution and consolidation of data should evaluate Veritas' SRNT 2.0. The product, which replaces Veritas' Replication Exec line, is well-designed for stability, scalability and low overhead, but this release has significant shortcomings. The next release, due in November, could be a real winner.
Short-term Business Impact // SRNT will immediately simplify and organize data consolidation and distribution across an entire enterprise network and allow for increased data availability.
Long-term Business Impact // High-growth businesses will find that SRNT scales quite easily and requires little training. However, as server farms grow, licencing costs will add up. And once a network exceeds 50 nodes, the company might need outside help to analyze network traffic patterns and plan for future growth.
Console is comprehensive and easy to use; performs TCP/IP-based data transfers quickly with low overhead.
Does not support Microsoft Clustering Services or registry replication; does not encrypt data; lacks virus scanning.
Veritas Software Corp.