[gpfsug-discuss] help/ advice with external helper apps for ILM policy engine

[Jan-Frode Myklebust]

> policy engine doesn’t appear to be able to access the extended file
attributes indicating which cloudpool a migrated file is in

I'm struggling to accept this -- but I no longer have any TCT systems to
check on. You seem to say there is an xattr that tells which cloudpool a
file is migrated to. Which xattr is this ? Could you give an example?
Looking into an old policy partition dump I have in my notes (tslspolict
gpfs0 --ptn gpfs0TctPartition -L), I see no relevant xattrs pointing at any
pools -- so maybe it's just being kept in some TCT database elsewhere?

But, for converting from TCT to AFM you could maybe just look for
files that are premigrated or migrated looking at MISC_ATTRIBUTES V for
fully migrated files:

define( is_migrated,    (MISC_ATTRIBUTES LIKE '%V%') )

and:

/* TCT needs timestamp comparison to decide if cloud version is same as
local version: */
define( is_premigrated_different, ((XATTR('dmapi.MCEA', 5, 1) == 'C') AND
(MTIME_FILE != MTIME_XATTR)))
define( is_premigrated_same, ((XATTR('dmapi.MCEA', 5, 1) == 'C') AND
(MTIME_FILE == MTIME_XATTR)))

I don't think these are set for AFM evicted files, as that's a very
different mechanism.

  -jf


On Wed, Dec 24, 2025 at 12:32 PM Paul Ward <p.ward at nhm.ac.uk> wrote:

> Yes I tried that first, but it seems from the testing I’ve done, the
> attributes I want are not accessible from the policy engine in 5.1.9.
> Co-pilot suggests they maybe in 5.2.x
> Which we cant go to until we’ve converted from TCT to AFM, which is what I
> need this for.
>
>
>
> Kindest regards,
>
> Paul
>
>
>
> Paul Ward
>
> TS Infrastructure Architect
>
> Natural History Museum
>
> T: 02079426450
>
> E: p.ward at nhm.ac.uk
>
>
>
> *From:* gpfsug-discuss <gpfsug-discuss-bounces at gpfsug.org> *On Behalf Of *Jan-Frode
> Myklebust
> *Sent:* 23 December 2025 21:50
> *To:* gpfsug main discussion list <gpfsug-discuss at gpfsug.org>
> *Subject:* Re: [gpfsug-discuss] help/ advice with external helper apps
> for ILM policy engine
>
>
>
> Policy engine can use xattrs using something like "WHERE
> xattr('user.xattrname') LIKE 'value'".
>
>
>
> I don't currently have any TCT systems available to check, but are there
> no xattrs you could use a xattr like above to figure out which pool it's
> in? Use f.ex. "mmlsattr -L -d filename" to check which xattrs are set for a
> given file.
>
>
>
>
>
>
>
>   -jf
>
> On Tue, Dec 23, 2025 at 11:19 AM Paul Ward <p.ward at nhm.ac.uk> wrote:
>
> Hi,
>
> has anyone written external helper apps for the ILM policy engine.
>
> we are running TCT, planning to move files from on-premise COS to AWS, but
> I need to detect which cloudpool the files are currently in.
> The policy engine doesn’t appear to be able to access the extended file
> attributes indicating which cloudpool a migrated file is in.
> So I am trying to use an external helper script, but execution of the
> policy seems to stall at the point it should use the helper script.
>
> I will also need to use a help app to move the files from COS to AWS as
> the mmcloudgateway CLI will recall then migrate, but the policy engine
> detects the files are already migrated so refuses to ‘migrate’ them again.
> I plan to call the CLI version
>
> Any advice?
>
>
>
> Kindest regards,
>
> Paul
>
>
>
> Paul Ward
>
> TS Infrastructure Architect
>
> Natural History Museum
>
> T: 02079426450
>
> E: p.ward at nhm.ac.uk
>
>
>
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