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EMI proposal for a Storage Accounting Record standard

EMI proposal for a Storage Accounting Record standard. Jon Kerr Nilsen Dept. of Physics, Univ. of Oslo On behalf of the EMI StAR team. Who?. EMI StAR team Paul Millar Ralph Müller - Pfefferkorn Zsolt Molnár Riccardo Zappi Jon Kerr Nilsen Henrik Thostrup Jensen (NDGF). Outline.

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EMI proposal for a Storage Accounting Record standard

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  1. EMI proposal for a Storage Accounting Record standard Jon Kerr Nilsen Dept. of Physics, Univ. of Oslo On behalf of the EMI StAR team

  2. Who? • EMI StAR team • Paul Millar • Ralph Müller-Pfefferkorn • ZsoltMolnár • Riccardo Zappi • Jon Kerr Nilsen • HenrikThostrupJensen (NDGF) Jon Kerr Nilsen

  3. Outline • Why storage accounting? • Storage accounting vs. job accounting • Processing model • Storage accounting work in EMI and OGF • StARproposal • Prototype and first feedback • Way forward Jon Kerr Nilsen

  4. Why storage accounting? • Storage resources are shared between organizations – more than one owner • Developing a storage infrastructure • We need to know how much storage space is used, by which group/user, on which storage media • To know where to put the money when increasing the storage space • To know who to ask for the money to increase the storage space • Basis for billing • Storage is expensive • Some non-academic resource owners may not like to give it away for free Jon Kerr Nilsen

  5. Accounting • Accounting is the recording and summarizing of the consumption of a resource by an individual user or a group of users • Typically used to find out who uses how much of a set of resources • Typically not used to find out how individual resource components are used Jon Kerr Nilsen

  6. Storage vs. job accounting Job accounting Storage accounting Storage accounting is the recording and summarizing of the consumption of a storage resource Storage usage varies in time – recorded usage is only relevant in a given time frame Data is rarely in finished state and can live for a long time Typically recorded through (in)frequent usage snapshots – high fluctuation rate No standardized way to record storage usage in a distributed environment • Job accounting is the recording and summarizing of the consumption of computing resources • Recording wall-time, cpu-time, etc. – strictly increasing values. • When a job finishes it stays finished • Typically measured per job – information readily available from local batch system • Standardized through UR1.0 Jon Kerr Nilsen

  7. Storage vs. job summary • Storage records must be treated different than compute records wrt. aggregation • Storage records need special treatment • Only valid between measurement time and expiration time • Can be invalidated if newer record is registered for same resource • Nontrivial processing model Jon Kerr Nilsen

  8. Processing model • Records can overlap in time – cannot simply sum up to identify total consumption • Must ask for a certain point in time and sum up the most recent, still-valid records • To get usage per time, you must choose a set of timestamps and repeat process per time stamp – numerical integration Jon Kerr Nilsen

  9. Processing model • Records can overlap in time – cannot simply sum up to identify total consumption • Must ask for a certain point in time and sum up the most recent, still-valid records • To get usage per time, you must choose a set of timestamps and repeat process per time stamp – numerical integration Jon Kerr Nilsen

  10. Processing model • Records can overlap in time – cannot simply sum up to identify total consumption • Must ask for a certain point in time and sum up the most recent, still-valid records • To get usage per time, you must choose a set of timestamps and repeat process per time stamp – numerical integration Jon Kerr Nilsen

  11. Processing model • Records can overlap in time – cannot simply sum up to identify total consumption • Must ask for a certain point in time and sum up the most recent, still-valid records • To get usage per time, you must choose a set of timestamps and repeat process per time stamp – numerical integration Jon Kerr Nilsen

  12. Processing model • Records can overlap in time – cannot simply sum up to identify total consumption • Must ask for a certain point in time and sum up the most recent, still-valid records • To get usage per time, you must choose a set of timestamps and repeat process per time stamp – numerical integration Jon Kerr Nilsen

  13. Processing model • Records can overlap in time – cannot simply sum up to identify total consumption • Must ask for a certain point in time and sum up the most recent, still-valid records • To get usage per time, you must choose a set of timestamps and repeat process per time stamp – numerical integration Jon Kerr Nilsen

  14. Processing model • Records can overlap in time – cannot simply sum up to identify total consumption • Must ask for a certain point in time and sum up the most recent, still-valid records • To get usage per time, you must choose a set of timestamps and repeat process per time stamp – numerical integration Jon Kerr Nilsen

  15. Storage accounting in EMI • From EMI Description of Work: • EMI will address known UR issues and extend accounting records to include VO-aware storage usage accounting • The refined and extended standard UR format, service interface and data transport protocol will be implemented in gLite, ARC, dCache and UNICORE • EMI will thus contribute to the definition of UR 2.0 of OGF Jon Kerr Nilsen

  16. Storage accounting in OGF • “Next Generation Usage Records” OGF session at OGF31 • Discussed the way forward for UR • A properly defined storage record and an improved compute record are good steps towards UR2.0 • Lessons learned in storage records can be ported back into compute records (e.g. long-lived services) • EMI will work actively to have standard ready before end of EMI • Being a highly active participant, EMI will co-chair the OGF UR-WG Jon Kerr Nilsen

  17. StAR • EMI is finalizing a proposal for a storage accounting record (StAR) • Contacted and received input from organizations and potential user groups • NDGF, OGF, EGI, OSG, INFN, CMS, ATLAS, … • Current draft: StAR-EMI-tech-doc-v7.pdf • Final version to be proposed to OGF as a standard • Will be implemented by EMI storage providers Jon Kerr Nilsen

  18. What StAR is not • To be able to arrive to a useful record in record time we need to limit the scope • Many interesting storage-related features to record • I/O (like in Amazon S3) • Metadata access (stat,ls) • Available space • File name • ... • Scope of StAR is limited to consumption of storage space Jon Kerr Nilsen

  19. StAR structure • Resource • Fields describing the system the resource was consumed on • StorageSystem, StorageShare • Resource consumption • How much of the described resource has been used • ResourceCapacityUsed, LogicalCapacityUsed • Consumption details • Fields describing what is consumed • StorageMedia, StorageClass, DirectoryPath, … • Identity • Describes the person or group accountable for the consumption • SubjectIdentity block (UserIdentity, Group, GroupAttribute, …) • Record identity and duration Jon Kerr Nilsen

  20. Local example <sr:StorageUsageRecord xmlns:sr="http://eu-emi.eu/namespaces/2011/02/storagerecord"> <sr:RecordIdentitysr:createTime="2010-11-09T09:06:52Z" sr:recordId="host.example.org/sr/87912469269276"/> <sr:StorageSystem>host.example.org</sr:StorageSystem> <sr:SubjectIdentity> <sr:LocalUser>johndoe</sr:LocalUser> </sr:SubjectIdentity> <sr:StorageMedia>ssd</sr:StorageMedia> <sr:FileCount>42</sr:FileCount> <sr:MeasureTime>2010-10-11T09:31:40Z</sr:MeasureTime> <sr:ValidDuration>PT3600S</sr:ValidDuration> <sr:ResourceCapacityUsed>913617</sr:ResourceCapacityUsed> </sr:StorageUsageRecord> Jon Kerr Nilsen

  21. Grid example <sr:StorageUsageRecord xmlns:sr="http://eu-emi.eu/namespaces/2011/02/storagerecord"> <sr:RecordIdentitysr:createTime="2010-11-09T09:06:52Z" sr:recordId="host.example.org/sr/87912469269276"/> <sr:StorageSystem>host.example.org</sr:StorageSystem> <sr:SubjectIdentity> <sr:Group>binarydataproject.example.org</sr:Group> <sr:GroupAttributesr:attributeType="subgroup">ukusers </sr:GroupAttribute> </sr:SubjectIdentity> <sr:StorageMedia>tape</sr:StorageMedia> <sr:FileCount>42</sr:FileCount> <sr:MeasureTime>2010-10-11T09:31:40Z</sr:MeasureTime> <sr:ValidDuration>PT3600S</sr:ValidDuration> <sr:ResourceCapacityUsed>913617</sr:ResourceCapacityUsed> </sr:StorageUsageRecord> Jon Kerr Nilsen

  22. Prototype implemented • NDGF already has working prototype • Using SGAS accounting service and data from NDGF dCache • Records inserted in SGAS, parsed and put into PostgreSQL DB • Querying data model with measure points and valid duration doable for anyone comfortable with putting joins in queries • Hackish record generation (simple SQL into dCache DB) • Still limited graphing possibilities Jon Kerr Nilsen

  23. Prototype implemented Usage (TB) Jon Kerr Nilsen

  24. First experiences from NDGF • Information available from records has limitations (we knew that) • Good for measuring actual usage • Good for measuring logical usage/VO • Logical usage/site/VO is more tricky • Measuring and aggregating logical usage is not straight-forward • Free space could be useful as well but this is tricky for same reasons as logical usage Jon Kerr Nilsen

  25. Local usage issue • The NDGF dCachesystem is composed of seven sites, each storing a lot of data • NDGF replicates all data which has been accessed within the last 30 days to two sites • NDGF needs usage per VO and per site Jon Kerr Nilsen

  26. Local usage issue • If a file is stored on site A and site B for a VO C, then what exactly is reported as logical usage for any of the sites for that VO? • Cannot say from record if file* is a replica or a logical file • May need hierarchy in the record to get clear answer • More complex, less intuitive and more error prone record • Different storage systems may have different hierarchies – generic data model will be REALLY complicated • We probably don’t want to go there Jon Kerr Nilsen

  27. Way forward • Definition of StAR is a first step to establish common storage accounting record • A step towards a common usage record (UR2.0) • Next jump (two steps in one go) • Propose StAR to OGF to start standardization process • Will take time • Will include further discussions • May lead to changes in StAR • EMI will take active part in this process • Draft has been made available through UR-WG mailing list • Will be made available in SourceForge • Implement StAR record into EMI storage middleware • EMI ends in two years • Want to gain user experience before end of EMI • Work already started outside EMI • Comments and input more than welcome throughout the process! Jon Kerr Nilsen

  28. Contact: emi-jra1-data-sar@eu-emi.eu Web page: http://twiki.cern.ch/twiki/bin/view/EMI/StorageAccounting Current StAR draft: http://twiki.cern.ch/twiki/pub/EMI/StorageAccounting/StAR-EMI-tech-doc-v7.pdfhttp://twiki.cern.ch/twiki/pub/EMI/StorageAccounting/StAR-EMI-tech-doc-v7.doc Thank you! Jon Kerr Nilsen

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