block level and file level transfer

[Jdsony5]

Hello guys,

whats the difference between file level transfer and

block level transfer? i just know that Fiber Channel SAN and iSCSI use

block level transfer and NAS uses file level but i don't the exact

differences between them. i googled but in vain. i was not happy with

what i got on google. any suggestions please

cheers

[weinstein5]

Welcoem to the Forums - The difference comes from the time when Storage Netwroks were first being developed - Two paths were developed - SAN and NAS each provided storage via a network- to understandthe difference you need to understand what command are transported across each network -

SAN - In a SAN the packet, either Firber Channel or iSCSI, is carrying a SCSI command which causes the SAN to return the approriate blocks

NAS - Only supports two protocols - SMBfor Windows oe NFS for Unix/Linux. ESX only uses NFS. So for NAS the command is no longer a SCSI command but a file system command - when the command reaches your NAS device the file system command is operated and the data is returned to your ESX host.

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[Jdsony5]

Thanks for the reply mate. thanks for your time

[weinstein5]

No worries - hope it is clear now -

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