PowerScale: Isilon: InsightIQ only tracks file system extensions uniquely if they have up to four characters by default

By default, Isilon's File System Analytic (FSA) reporting system tracks and caps delineation of unique files with file extensions longer than four characters.

This is due to the InsightIQ (IIQ) reporting pulling from Isilon File Systems Analytics (FSA) reporting, which by default stops at four characters.

What this means in practice is that if you have files with (Access 2007/2010 Database file) .accd and .accdb file extensions, in standard configurations the FSA report will combine the .accd and .accdb files (or .accdc, .accdd, and so on) under the .accd objects. This is due to FSA, by default, stopping analysis at four characters for performance considerations. 

The simple workaround for this is to change the following gconfig value with the following isi_gconfig command:

isi_gconfig fsa.file_ext_char_cnt=5

This causes the FSA system, when running, to break out extensions up to five characters. This, will pass downstream to InsightIQ. There are no relevant InsightIQ settings for this. The information is entirely supplied by Isilon's FSA reporting. 

An important consideration here is that by increasing this value, you increase the amount of workload and overhead for relevant SQL operations related to the generation of FSA reporting. This can potentially lead to performance impacts, and possibly negative ones.

There is no way--at all--for Dell to gauge, determine, or evaluate ahead of time the risk of such performance impacts, if they will even happen, or the potential scope of impact. Customers may see no actual change or can see substantial issues that are related to FSA performance. Each environment is unique.

If the change is made and performance impacts are seen afterward, the only remediation is to undo the change and lower that value again. Dell Support asks that the change be rolled back if implemented, so the client can reevaluate performance again. There is presently no other mitigation if this change causes an impact.