[gpfsug-discuss] File_heat for GPFS File Systems

[Andreas Landhäußer]

as far as I understand, if a file gets hot again, there is no rule for 
putting the file back into a faster storage device?

We would like having something like a storage elevator depending on the 
fileheat.

In our setup, customer likes to migrate/move data even when the the 
threshold is not hit, just because it's cold and the price of the 
storage is less.


On 27.09.2016 16:25, Marc A Kaplan wrote:
>
> You asked ...  "We are wishing to migrate data according to the heat 
> onto different
> storage categories (expensive --> cheap devices)"
>
>
> We suggest a policy rule like this:
>
> Rule 'm' Migrate From Pool 'Expensive'  To Pool 'Thrifty' 
>  Threshold(90,75) Weight(-FILE_HEAT) /* minus sign! */
>
>
> Which you can interpret as:
>
> When The 'Expensive' pool is 90% or more full, Migrate the lowest heat 
> (coldest!) files to pool 'Thrifty', until
> the occupancy of 'Expensive' has been reduced to 75%.
>
> The concepts of Threshold and Weight have been in the produce since 
> the MIGRATE rule was introduced.
>
> Another concept we introduced at the same time as FILE_HEAT was GROUP 
> POOL.  We've had little feedback and very
> few questions about this, so either it works great or is not being 
> used much. (Maybe both are true ;-) )
>
> GROUP POOL migration is documented in the Information Lifecycle 
> Management chapter along with the other elements of the policy rules.
>
> In the 4.2.1 doc we suggest you can "repack" several pools with one 
> GROUP POOL rule and one MIGRATE rule like this:
>
> You can “repack” a group pool by *WEIGHT*. Migrate files of higher 
> weight to preferred disk pools
> by specifying a group pool as both the source and the target of a 
> *MIGRATE *rule.
>
> rule ’grpdef’ GROUP POOL ’gpool’ IS ’ssd’ LIMIT(90) THEN ’fast’ 
> LIMIT(85) THEN ’sata’
> rule ’repack’ MIGRATE FROM POOL ’gpool’ TO POOL ’gpool’ WEIGHT(FILE_HEAT)
>
>
> This should rank all the files in the three pools from hottest to 
> coldest, and migrate them
> as necessary (if feasible) so that 'ssd' is up to 90% full of the 
> hottest, 'fast' is up to 85% full of the next
> most hot, and the coolest files will be migrated to 'sata'.
>
>
>
>

-- 
Andreas Landhäußer                +49 151 12133027 (mobile)
alandhae at gmx.de

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://gpfsug.org/pipermail/gpfsug-discuss_gpfsug.org/attachments/20160927/edba67ce/attachment-0002.htm>