[LU-13853] Describe syntax for rule based auto PCC caching

Wed, 5 Aug 2020 08:10:32 +0000

Where user can find patterns and syntax to describe rules?

According to the task https://jira.whamcloud.com/browse/LU-10918

user has some form of language. So it is unclear what elements and what combinations can be applied, how to form rules. This can be included in Lustre manual with examples or in other document. (wiki page? )

For instance fname={*.doc} is applicable and works, but what about patterns such as

"fname={file*} "fname={*file} ?

For two last patterns rule do not work. Consider example below:

/usr/sbin/lctl pcc list /mnt/lustre

/usr/sbin/lctl pcc add /mnt/lustre /mnt/pccro -p "fname={file*} roid=4"
/usr/sbin/lctl pcc list /mnt/lustre 

pcc:  
-    pccpath: /mnt/pccro    
hsmtool: posix    
rwid: 4    
roid: 4    
flags: 3e    
autocache: fname={file*}

After file was created echo > /mnt/lustre/file1

pdsh -w trevis-59vm[10-12] lfs pcc state /mnt/lustre/file1

trevis-59vm11: file: /mnt/lustre/file1, type: none

trevis-59vm12: file: /mnt/lustre/file1, type: none

trevis-59vm10: file: /mnt/lustre/file1, type: none

From my point of view

Expected: /mnt/lustre/file1 in cached state

So it is good to have answerst to questions below:

What elements are available in fname? Is it globbing *, ?, [] syntax supported? or it is some form of custom syntax?

Is it possible to use directory names and slash "/" symbol in pattern?
What other syntax elements are available? logical operators? (not, or, and ?) closing elements {} - are they necessary?)

What is other keywords uid, projid etc?
Does user need to specify this rule at all? Why it rule can't be empty?

Whamcloud Community JIRA

[LU-13853] Describe syntax for rule based auto PCC caching