Write Back Caching on Hard Disks

[Gabe Matteson]

the write back caching feature for the hard disks in device manager, does
that caching only occur in the memory of the OS, or does that write back
caching on device manager work in conjunction with the raid controller
battery backed cache? or does the raid controller cache only work at the
hardware level for the disks and have nothing to do with the device manager
write back caching feature?

 

[Rick]

the write back caching feature for the hard disks in device manager, does
that caching only occur in the memory of the OS

yes.

, or does that write back

caching on device manager work in conjunction with the raid controller
battery backed cache?

no.

or does the raid controller cache only work at the

hardware level for the disks and have nothing to do with the device manager
write back caching feature?

yes.

Rick

 

[Dan Lovinger [MSFT]]

Its exactly the other way around. The cache contolled in the device manager
is the device's cache - not the operating system's file cache.

 

[Rick]

What device are you referring to, the drive or the controller?
Both (potentially, or at least usually in the case of RAID
controllers) have caches. I assumed the Device Manager
option controlled the drive's cache, while the bios option on
the RAID controller controlled its own caching?

Is a comprehensive summary of this topic available somewhere
in MS's KB?

Rick

 

[Dan Lovinger [MSFT]]

The drive. Caches on controllers aren't controlled from the drive's property
page. The storage folks tell me that controller caches are usually exposed
through custom UI that each manufacturer provides.

I don't know of any KB, but ones may exist talking about parts of what we're
talking about here.

Note that the drive cache here is the one *on* the drive - not in the
machine's RAM.

--
Dan Lovinger
Microsoft Corporation
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