HP NetRAID-4M Configuration and Upgrade Guide (Release 5)

Chapter 9 Issues and Problem Resolution

database is not actually damaged. Note that this problem only occurs if you are

running version 5.5.2608.0 of the Ese.dll file. When Exchange Server makes a

request to the hardware to read data from the database, it compares the returned data

page and the calculated data checksum with the page number and checksum that

were placed on the page when it was written. If a mismatch is detected, a -1018 error

is generated. Note that this warning indicates that only the verification has failed. It

is possible that the data on disk has not been damaged, but that a transient error has

occurred in the data delivery system.

Hypothesis: “This problem occurs when the buffer for the Windows NT Backup

program is set to a value greater than 512 KB.”

Microsoft tested this hypothesis with a “cause and effect” experiment, by inducing

drive defects by tapping on the disk drives. The tapping experiment did cause 1018

errors. This led Adaptec to investigate two problems in the firmware.

Problem #1: artificially induced error code 1018. Fixed in Release 3.

Problem #2: potential for data corruption. This scenario requires a mirror set, two

drives, and five criteria. Fixed in Release 3.

1. The mirror set must have one bad sector on each drive.

2. The offset between the two bad sectors must be at least one but within 128.

3. The data in the higher logical block address is not ECC correctable.

4. The write operation must be part of a cache flush.

5. The original user I/O request must consist of at least two writes, <= 512 bytes

each.

Impact to Customer: Serious. This bug is believed to result in data corruption.

Frequency of Occurrence: Very rare. The probably of the exact five criteria lining

up and generating this error is extremely small.

Workaround: If additional confirmation of data damage is required, Microsoft

recommends that you run the Esefile utility. This utility is available in the Support

directory of Exchange Server 5.5 Service Pack 3.

Additional information can be found on the Microsoft web page:

1. Go to http://support.microsoft.com/

2. Search for Knowledge Base Article Number Q237953.

38 Miniport driver, performance enhancement available