Max,

Benefits:

ZCS and BCS drives both offer the added reliability of checksums, which allow WAFL to confirm that the data a hard-drive returns is what was written to in in the first place.

BCS drives are formatted to allow this checksum to be stored with the data, rather than in a separate block, so BCS drives offer the same protection but with potentially increased performance, depending on workload.

Limitations:

BCS drives can be used in ZCS volumes but will be treated as a ZCS drive.

A filer with BCS volumes must use DOT6.0.1 or above and cannot be reverted to 5.x

BCS drives CANNOT be used on pre 6.0.1 filers.

Other Questions:

A FAQ on Zoned and Block Checksums using Data ONTAP OS 6.0.1 may be found in the NOW knowledge base: http://now.netapp.com/Knowledgebase/solutionarea.asp?id=ntapcs753

Regards, Matt.

-----Original Message----- From: max chan [mailto:maxchan0@yahoo.com] Sent: 06 April 2001 10:48 To: toasters@mathworks.com Subject: Block checksum and Zone checksum drive

Dear all,

Is there any different for Block checksum and Zone checksum drive? in term of preformance, reliability, limitation etc.. If i use ontap 6x, which one should i chose?

Max

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