1. Armenuhi Abramyan, Narine Manukyan ALICE team of A.I. Alikhanian National Scientific Laboratory {aabramya, nmanukya}@mail.yerphi.am

2. Offline weekly meeting 12 August 2013 2 Solution: Regular (partial) cleaning of SEs by removing certain portion of replicas Step one: Definition of data files (DFs) and data file sets (FSs), subjects to removal Step two: Construction of the removal and cleaning general scheme Problem: Replication of data files -> Repletion of SEs -> Prevention of further inflow of files to these SEs Problem: Replication of data files -> Repletion of SEs -> Prevention of further inflow of files to these SEs Step three: Determination of the order of the FSs’ removal (replicas killing queuing    ) Step two: Algorithm to determine the portion of replicas of DFSs to remove from SEs Step three: Algorithm to determine the portion of replicas of DFSs to remove from SEs

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4. 4 ‘Centrally’ created DFs: ESD.root; AOD.root; QA.root; OCDB.root ‘Centrally’ created DFs: ESD.root; AOD.root; QA.root; OCDB.root Volumes occupied by DFs in LHC12c directory: LHC12c286 TB(100.00 %) __________________________________________ RAW S 205.0 TB(71.7 %) __________________________________________ ESDs64.4 TB (22.5 %) AODs13.0 TB(4.54 %) QAs3.55 TB(1.23 %) OCDBs0.03 TB(0.02 %) __________________________________________ PWG directories0.02 TB(0.01%) Volumes occupied by DFs in LHC12c directory: LHC12c286 TB(100.00 %) __________________________________________ RAW S 205.0 TB(71.7 %) __________________________________________ ESDs64.4 TB (22.5 %) AODs13.0 TB(4.54 %) QAs3.55 TB(1.23 %) OCDBs0.03 TB(0.02 %) __________________________________________ PWG directories0.02 TB(0.01%) PWG-created root files(?) Data File (DF) = any.root file What about user-created root files(?). How much volume do they occupy?

5. Offline weekly meeting 12 August 2013 5 Elementary File Sets (EFSs) = zip archives of DF s ( Σ of output.root files of each job). In AliEn, the data replication is done by these units. Elementary File Sets (EFSs) = zip archives of DF s ( Σ of output.root files of each job). In AliEn, the data replication is done by these units. A lowest order file whose content is considered as a whole Examples of Basic Data Files: AOD.root; ESD.root; QA.root A lowest order file whose content is considered as a whole Examples of Basic Data Files: AOD.root; ESD.root; QA.root Types of archives in AliEn: root_archive.zip= set of ESD | AOD | QA | PWG- created | user- created DFs aod_archive.zip= set of AOD type DFs QA_archive.zip = set of QA related DFs log_archive | log_archive.zip = set of log files Types of archives in AliEn: root_archive.zip= set of ESD | AOD | QA | PWG- created | user- created DFs aod_archive.zip= set of AOD type DFs QA_archive.zip = set of QA related DFs log_archive | log_archive.zip = set of log files Suggestions of CFSs containing the same types of EFSs: Run_AOD, Period_AOD - Full set of AOD type EFSs in Run, Period Run_ESD, Period_ESD - Full set of ESDs type EFS in Run, Period Suggestions of CFSs containing the same types of EFSs: Run_AOD, Period_AOD - Full set of AOD type EFSs in Run, Period Run_ESD, Period_ESD - Full set of ESDs type EFS in Run, Period To discuss and decide: The removal is convenient to be performed not on the level of the EFSs themselves, but in their (meaningful) combinations = Composite File Sets (CFSs) To discuss and decide: The removal is convenient to be performed not on the level of the EFSs themselves, but in their (meaningful) combinations = Composite File Sets (CFSs)

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7. 7 1.How many custodial replicas (CMS parlance) of CFSs should be kept? 2.Should the number of custodial replicas be dependent on the type of CFS (AOD,…. OCDB,..)? 3.Where to keep custodial replicas? ( on Tier1s? Tier2s with low CPU?) 1.How many custodial replicas (CMS parlance) of CFSs should be kept? 2.Should the number of custodial replicas be dependent on the type of CFS (AOD,…. OCDB,..)? 3.Where to keep custodial replicas? ( on Tier1s? Tier2s with low CPU?)

8. Offline weekly meeting 12 August 2013 Global removal = removal from AliEn, without taking care of the state of individual SEs. In Global removal approach, any CFS can be removed entirely! An ordered removal of replicas of the same archive.zip: 1.One keeps custodial replica(s) 2.One takes into account additional criteria related to the individual sites: a) Repletion state of the sites where the replicas are placed; b) Number of the failures to access the replicas on the sites they are placed. ……………… An ordered removal of replicas of the same archive.zip: 1.One keeps custodial replica(s) 2.One takes into account additional criteria related to the individual sites: a) Repletion state of the sites where the replicas are placed; b) Number of the failures to access the replicas on the sites they are placed. ……………… SE1 1+1 CFS archive1.zip SE2 SE1 SEN 2 SEN 1 SE3 archiveN.zip … 1 CFS archive1.zip SE2 SEN 2 archiveN.zip … archive1.zip 1+1 CFS SE2 SE1 SEN 2 SEN 1 archiveN.zip … A problem: Which one of the replicas of an archive.zip to remove?

9. Offline weekly meeting 12 August 2013 9 Since the EFSs entering CFS are dispersed by different SEs, an entire removal of a CFS is not possible in the local approach. Removal of a CFS can be made possible only in a correlated (with the other SEs) manner. No ordering of replicas of the same archive.zip for removal is needed. A single restriction- Custodial replicas are not removed. The drawback of local approach! If we give priority to local freeing but not to the removal of an entire CFS, then only part of the EFSs entering a CFS can be removed. As a result, we will have ‘amputated’ CFSs. Since the EFSs entering CFS are dispersed by different SEs, an entire removal of a CFS is not possible in the local approach. Removal of a CFS can be made possible only in a correlated (with the other SEs) manner. No ordering of replicas of the same archive.zip for removal is needed. A single restriction- Custodial replicas are not removed. The drawback of local approach! If we give priority to local freeing but not to the removal of an entire CFS, then only part of the EFSs entering a CFS can be removed. As a result, we will have ‘amputated’ CFSs. 1+1 CFS archive1.zip SE2 SE1 SEN 2 SEN 1 archiveN.zip … 1’ CFS archive1.zip … SE2 1 CFS archive1.zip SE1 SEN 1 archiveN.zip … (amputated CFS)

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11. Offline weekly meeting 12 August 2013 11 Dataset: The largest, homogeneous collection of files, related to a same trigger stream, processing campaign, output data format. The replica removal in CMS is done by datasets - Analog of CFS. (Note: One entire replica of a dataset is stored on one SE) Analog of EFS - Block: The smallest unit in computing space which corresponds to a group of files likely to be accessed together. Files are grouped in blocks for bulk data management reasons Replica removal in CMS: - Local removal scheme Only Tier-2 sites are cleaned, with the following conditions: 1 The removal procedure starts if the site has less than 10% (or 15 TB for small SEs) of free space. 2. The removal procedure ends when 30 % (or 25 TB) of site space is freed. Only Tier-2 sites are cleaned, with the following conditions: 1 The removal procedure starts if the site has less than 10% (or 15 TB for small SEs) of free space. 2. The removal procedure ends when 30 % (or 25 TB) of site space is freed.

12. Offline weekly meeting 12 August 2013 12 The ordering of CFSs for removal can be done using the Popularity notion. An example of popularity construction for a CFS is the summary number of calls to Data Files (summary number of occurrences of their LFNs) entering that CFS. Realistic verification of our models and final construction is possible only on the base of fine-grained monitoring data on EFSs. We are considering several (popularity - based) models for the solution of the ordering problem.

13. Offline weekly meeting 12 August 2013 13 The purpose of the File Access Monitoring Service is to monitor the frequency of the accesses to the files in the AliEn File Catalogue. The work on the development of FAMoS has been started on July 2012; The code has been included in AliEn v2.20 (on October 2012) and AliEn v2.21 (on January 2013); A part of FAMoS, which records the details on the file accesses has been deployed on all AliEn central servers on 6th of August 2013. Thanks to Miguel. The work on the development of FAMoS has been started on July 2012; The code has been included in AliEn v2.20 (on October 2012) and AliEn v2.21 (on January 2013); A part of FAMoS, which records the details on the file accesses has been deployed on all AliEn central servers on 6th of August 2013. Thanks to Miguel.

14. Offline weekly meeting 12 August 2013 14 AttributeDescription File nameThe LFN of a file SE nameName of SE from where file was accessed User nameName of user by whom file was accessed Access TimeTime and date when the file was accessed Operation typeRead or write access Operation resultSuccessful or failed access The source: Your comments and suggestions would be highly appreciated !!! Since all the accesses to the files within File Catalogue are authenticated by the AliEn Authentication (Authen) service, a plugin (called attributes) has been included in the Authen service in order to record the values of specified attributes (into “Authen_ops" daily log files).

15. Offline weekly meeting 12 August 2013 15 Data type Category Files within this paths in AliEn File Catalogue _AOD Real data: /alice/data/…/ /…/ESDs/…/AOD /… /alice/data/…/ /…/AliAOD.root Simulated data: /alice/sim/…/ /…/AliAOD.root _ESDReal data: /alice/data/…/ /…/ESDs/… (except files of AOD category) /alice/data/…/ /…/AliESD.root Simulated data: /alice/sim/…/ /…/ALiESD.root COND /alice/…/OCDB/… /alice/…/CDB/… USER /alice/cern.ch/user/… OTHERother paths

16. Offline weekly meeting 12 August 2013 16 /alice/packages/* *.par */bin/* *.log *log_archive* *validation.sh*.rc *.sh*.jdl*.xml *.C *.h*.cxx /alice/packages/* *.par */bin/* *.log *log_archive* *validation.sh*.rc *.sh*.jdl*.xml *.C *.h*.cxx They are ~94 % of accesses!!! Suggested filters:

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