Disk Cache Parameter

[saurabhbhattach]

Hi, Please explain what is a Disk cache parameter(s) and how can we use them?

[Ranjna Aggarwal]

Disk Cache:-

               The function of cache is to act as a buffer between a relatively fast device and a relatively slow one. For hard disks, the cache is used to hold the results of recent reads from the disk, and also to "pre-fetch" information that is likely to be requested in the near future, for example, the sector or sectors immediately after the one just requested.The use of cache improves performance of any hard disk, by reducing the number of physical accesses to the disk on repeated reads and allowing data to stream from the disk uninterrupted when the bus is busy.

[saurabhbhattach]

Hi Ranjna, Thanks for your reply but my question was not what is a disk cache, rather my question is related to Disk cache parameters regarding Esxi 5.0 and how we can use them?

[rickardnobel]

saurabhbhattacharya wrote:

rather my question is related to Disk cache parameters regarding Esxi 5.0 and how we can use them?

Could you clarify some more which disks you are talking about in this case? Is it local disks inside the ESXi hosts or SAN devices?

[saurabhbhattach]

Hi Rikard,

Its related to SAN storage devices in the environment.

[rickardnobel]

saurabhbhattacharya wrote:

Its related to SAN storage devices in the environment.

So you have questions about how to configure the SAN cache settings to work with ESXi?

[saurabhbhattach]

Hi Rikard,

Yes my question is regarding how to configure it on Storage if lets say I am a SAN admin or if a SAN admin has configured those parameters how it might affect a Vmware Admin. Is there any guide which explains different options and their repurcations.

[rickardnobel]

saurabhbhattacharya wrote:

Yes my question is regarding how to configure it on Storage if lets say I am a SAN admin or if a SAN admin has configured those parameters how it might affect a Vmware Admin. Is there any guide which explains different options and their repurcations.

Since this is very specific to your type of SAN there are unfortunately no single answer to that. The best way is to check with the storage vendor and see how they recommend the SAN, including the cache, to be configured for optimal use with vSphere.