SQL Server Performance

Rewinder Database Review

Discussion in 'Third Party Tools' started by bradmcgehee, Jul 11, 2003.

  1. bradmcgehee New Member

    Product review contributed by Michael Xu

    I have recently evaluated a SQL database recovery tool called Rewinder, that I thought the members of this forum would find interesting.

    The unique part of this product is instead of backing up/restoring a full database image, it continually captures those data page changes on SQL database into a space called “spool file”. When recovering a database, it just rolls back those changes to the point before the database corruptions occurs, so it makes recovering a hundred gigabytes database in several minutes possible.

    During my evaluation, I created a test script, importing more than 20 millions records into a 120G test database, then dropped and then recovered thedata. My test sever is a 2 way SQL 2000 Enterprise box, with 500G of storage on a SAN

    I am deeply impressed by the ability of Rewinder to recovery dropped/truncated tables. For example, I can easily recover a very large table (over 100M rows) in several minutes. In our environment, there are dozens of database size over 200G, so the quick recovery ability on large database is extremely valuable for us.

    However, this kind of technology will not provide protection against physical damage. In addition, I feel this product need improved stability, as is still new. I found bugs during my testing, such as the spool file size refuses to go over 850M even it is set up larger than that. Also, the rewind process failed sometimes without a detailed explanation, etc. The documentation is also not detailed enough for troubleshooting.

    Here is my rating on this product base on different categories

    Note: (1 to 5, from poor to excellent)

    1) Ability to recovery dropped/truncated tables, or to roll back operation.

    Rating: 5 (excellent).

    This feature is the highlight of this product. Based on flexibility and recovery duration, the SQL server standard recovery process can not compete with it

    2) Data integrity and consistency.

    Rating: 5 (excellent)

    It rolls back the whole database to a certain point time, hence ensures data integrity.

    3) Stability

    Rating: 2 (Poor)

    The current version is 1.5. I can not achieve 100% success rate during testing. There are other problems, such as not being able to roll back to 4 or 5 hours ago if testing server is continually under heavy stress.

    4) Documentation

    Rating: 2 (Poor)

    There are no rich content or online documentation. Too simple to be used for troubleshooting.

    5) Space Usage

    Rating: 3 (Average)

    According my test, the spool file size is about 3 to 4 times larger than the imported tables size. So to keep one day rewind data in our environment, about 30G to 50G of space is needed.

    6) Resource Usage

    Rating: 3 (Average)

    CPU usage is low, disk I/O high.

    The idea and technology used by this product is amazing, it is ideal to recovery database to a nearly passed time point, which the standard SQL recovery process can not compete on this point. It is even more valuable in our environment as our DB size is too big; a standard database restoration runs too long. However, the current Rewinder version seems not matured enough yet and needs improved stability. If you are not rushing to jump on this kind of solution now, you can wait for a while until it becomes more matured and more stable in near future.

    Michael Xu's biography: Michael has worked for DoubleClick Inc. for 4 years as a database administrator and manage over 3TB of OLTP SQL databases. He focuses on database disaster recovery, performance turning, and new technology/products research.

    Brad M. McGehee, MVP
  2. vbkenya New Member

    Any links or invitations to 'test' Rewinder?

    Nathan H.O.

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