From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Barton Date: Fri, 11 Jul 2008 10:05:02 +0100 Subject: [Lustre-devel] How store HSM metadata in MDT In-Reply-To: <48761DB6.4010207@fnal.gov> References: <48761DB6.4010207@fnal.gov> Message-ID: <00d001c8e335$341ff2e0$0281a8c0@ebpc> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org > For Lustre HSM project, it will be needed to store, for each file, a > list of information describing how many copies the file has in the HSM, > what is their HSM ID, the copy date, and so on. This data could easily > reach 500 bytes (I think we will need between 40 and 50 bytes per HSM > copy, and we should be able to save at least 10 copies, surely more). > The question is: where could we store this data on MDT, in which place > (EA?) and how manage this. Storing information about > 1 HSM copy violates one of our groundrules... > 3. The file system only has attributes to indicate the state of the primary > archived copy (probably the last fully archived copy of the file), and can > retrieve that file on demand (without user intervention). Cheers, Eric