Storage Management TEG: Questionnaire Level 1 - Andrew Lahiff

This twiki is to collect the input of Andrew Lahiff. Please answer the questions below. For more information, please refer to the Storage TEG main twiki.

Question 1

- In your view, what are the 3 main current issues in Storage Management (SM)?

My answer:

• Complexity: this can lead to longer than desired downtimes while problems are being investigated.
• Handling upgrades: draining of older diskservers onto newer generations is quite a lengthy process. Similarly for migration between tape media. (An extension of this would be the difficulties arising from the need for migrating petabytes of data from one storage system to another if a site were to move to a different storage technology).
• The variety of issues caused by increasing disk sizes, such as (a) any diskserver interventions result in larger numbers of files being inacessible to the experiment, (b) failure of a diskserver could result in larger data loss, (c) reduction in performance (network bandwidth, job slots, ...) for a given total capacity.

Question 2

- What is the greatest future challenge which would greatly impact the SM sector?

My answer:

Changing future workflows and requirements and increased data access demands.

Question 3

- What is your site/experiment/middleware currently working on in SM?

My answer:

The RAL Tier-1 is currently using CASTOR 2.1.10-1, and will soon upgrade to 2.1.11.

Question 4

- What are the big developments that you would like to see from your site/experiment/storage system in the next 5 years?

My answer:

Deprecate CASTOR for disk only storage in favour of another solution. Considering alternative technologies such as dCache, EOS, Hadoop, ...

Question 5

- In your experience and area of competence, what are the (up to) 3 main successes in SM so far?

My answer:

Put here your answer

Question 6

- In your experience and area of competence, what are the (up to) 3 main failures or things you would like to see changed in SM so far?

My answer:

• Diskservers in fixed space tokens which cannot be moved without time-consuming draining taking place. In some situations it might be better if diskservers could be assigned to space tokens dynamically in order to cope with the continually changing needs of experiments.

That's it!

Thanks! Feel free to edit again at any time, until the date of the kick-off meeting.

-- DanieleBonacorsi - November 2011