Will ELFI work with gLite middleware?

Yes. ELFI is developed to be an easy interface to the gLite Storage Elements.

Does ELFI perform caching?

At present, no. There is some limited form of caching, in that ELFI will cache the results of a directory listing (i.e., the results of an ls command) and, in some cases,

There are plans to implement a caching scheme in version 2.0, so stay tuned. (You can inquire about the current development status on the ELFI mailing list, however.)

Does ELFI work with a "classic" SE?

Yes, but you will need to install the GSI-enabled RFIO server on it (that's the DPM-rfio-server RPM), which is not presently installed by default on gLite SEs?.

Does ELFI work with DPM/dCache/StoRM?/etc.?

ELFI should work with any SRM server running version 2.1.1 or 2.2 of the SRM standard protocol. However, there are many interoperability issues among SRM implementations (including the lack of reference clients); here's the result of our tests:

CASTOR-SRM

Completely untested. If you wish to contribute access to your site for the tests, please tell the developers

DPM

Tested version 1.5.7: at present, only partially working.

dCache

Completely untested. If you wish to contribute access to your site for the tests, please tell the developers

StoRM?

Perfectly working. The EGRID VO is using it in its production infrastructure.

Is ELFI interoperable with lcg-utils?

Yes. You can do part of your data management with lcg-utils and part with ELFI; each one will see the changes done by the other.

Note that, as of gLite-3.0.4, lcg-utils only works with SRMv1? servers and the transfer protocol GridFTP?, whereas ELFI only works with SRMv2? servers and the transfer protocol RFIO/GSI, so the two suits actually complement each other, they are not alternative!

Can you access a file by GUID?

This is not supported, and we have no plans to add such a feature in the short term. (You are welcome to contribute it, however -- please inquire on the ELFI mailing list.)

When accessing a file by LFN, which replica is selected?

The replica selection algorithm chooses replicas based on the SE where they reside. SEs? are selected in this order of preference:

• the default SE;
• the SE having the same DNS domain name as the host ELFI is running on;
• the first SE returned by the query to the BDII