Site

Question ________________________________Response__________________________________
Site and Endpoints
What is the site name? KR-KISTI-GSDC-01 (WLCG Entry), KISTI_GSDC (ALICE Entry)
Which endpoint URLs do your archival systems expose? root://xht1201.sdfarm.kr:1094 (XRootD)
How is tape storage selected for a write (choice of endpoint, specification of a spacetoken, namespace prefix). We have different endpoint between disk and tape storage: root://xht1201.sdfarm.kr (for tape); root://alice-t1-xrdr01.sdfarm.kr (for disk)
Queue
What limits should clients respect? For the moment, any limits are not enforced to client side (experiment).
---> Max number of outstanding requests in number of files or data volume  
---> Max submission rate for recalls or queries  
---> Min/Max bulk request size (srmBringOnline or equivalent) in files or data volume  
Should clients back off under certain circumstances? In case of maintenance, we may request the clients to pause their actions
---> How is this signalled to client? We inform via directly e-mail to experiment management
---> For which operations? Maintenance e.g. urgent security update or required upgrade of systems: xrootd clusters or backend filesystems...
Is it advantageous to group requests by a particular criterion (e.g. tape family, date)?  
---> What criterion?  
Prioritisation
Can you handle priority requests? No. So far we have not been asked for any priority related matters. It is because we only support one experiment (ALICE) for now.
---> How is this requested?  
Protocol support
Are there any unsupported or partially supported operations (e.g. pinning) ?  
Timeouts
What timeouts do you recommend? at least 100 seconds? including the read-out time from cartridge and stage-in to tape buffer.
Do you have hardcoded or default timeouts? No, we don't.
Operations and metrics
Can you provide total sum of data stored by VO in the archive to 100TB accuracy? 2,983 TB / 3,200 TB (93%)
Can you provide space occupied on tapes by VO (includes deleted data, but not yet reclaimed space) to 100TB accuracy? 2,983 TB for ALICE VO
How do you allocate free tape space to VOs? Currently we support only one experiment (ALICE), all free tape space is allocated to ALICE VO.
What is the frequency with which you run repack operations to reclaim space on tapes after data deletion?  
Recommendations for clients
Recommendation 1  
---> Information required by users to follow advice  
Recommendation 2  
Buffer Management
Should a client stop submitting recalls if the available buffer space reaches a threshold?  
---> How can a client determine the buffer used and free space?  
---> What is the threshold (high water mark)?  
---> When should the client restart submission (low water mark)?  
If the client does not have to back off on a full buffer, and you support pinning, how is the buffer managed?  
---> Is data moved from buffer to another local disk, either by the HSM or by an external agent?  
Additional questions
Should any other questions appear in subsequent iterations of this survey?  
-- OliverKeeble - 2018-01-30
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Topic revision: r5 - 2018-04-19 - OliverKeeble
 
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