How to make a file 'sticky' in a Relay cache?

(imported topic written by Tim.Rice)

We are preparing to start a process using OSD to upgrade thousands of workstations (not all at once) from WinXP to Win7

The Image we are going to deploy is upwards of 6G. We’re going to use a ‘special’ relay with SSD’s to minimize ‘thrash’ and maximize throughput. What we would like to avoid is the Relay having to ‘re-cache’ the OSD .WIM.BFOSD file each night prior to it being distributed to the targeted endpoints.

All the machines to be images in a given cycle will be manually pointed to the Relay with Solid State Drives. We can set the Cache on the Relay, but we wanted to make sure that the big WIM file never falls out of the cache. No matter what.


(imported comment written by

Hi Tim,

From OSd point of view just some notes: you may force Image PreCache to be sure file is on the ‘Special’ SSD-Relay. If file is there on the cache, it will not be precached again and the “pre-cache” action should only take a while. (Anyway this will not ensure file is not removed, but forcing precache will make you sure file is there prior to start the Reimaging).

From IEM Relay cache managment point of view (I am not an expert) but looking here
I am proposing my idea: together with setting a large Relay cache size, may be a periodic task on the relay just “touching” the WIM.BFOSD updates the last modified date and may be make your file being one of the last recently updated then not being removed…(just thinking)



(imported comment written by Tim.Rice)

I suppose the next question would be, does the Relay keep track of when files are used, or does it leave that function to the OS?

In other words, can I use something like the “touch” command from
to reset the “Date Accessed” property on the disk and have the Relay service leave the file alone?

(imported comment written by jgstew)

I wonder how this works as well.

I imagine as long as the relay cache is large enough, or not enough things are asked for to fill up the cache and need that 6gb of space, then it should always be there.

(imported comment written by

I agree that having a large enough relay cache should preserve file from being removed.

About the “Date accessed” in the link above I saw

“the TEM Relay will remove the least recently used file in an effort to maximize the cache efficiency”

so I guess it might work to just “touch” it