1. Overview of DLSS Workshop
Don Petravick
FNAL
Office of Science Data Management Workshop

2. D. Petravick -- Office of Science Data Management Workshop
DLSS
What was it?
DLSS Disk in Large Scale Storage Systems
Feb 19-20
Hosted by NASA Goddard
Agenda
Government Requirements, Cost, Performance, Reliability, File Systems, Security, Legal Requirements.
I’ll present to my own schema.
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

3. Government Requirements
Evident difference between defense type systems and scientific systems.
Defense type systems
stringent and increasing security requirements,
kernel level file protections, etc.
Science
more able to exploit middleware approaches
file systems implemented in middleware.
Some frustration with the nature of the POSIX file interface.
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

4. D. Petravick -- Office of Science Data Management Workshop
Technology
Talk by STK about tape. (B. Raymond)
Disk
Discriminate by market, not by interface
“personal”, Enterprise.
Disk qualities differ depending on market
Talk by D. Anderson (Seagate) about interfaces and features in disks.
“Disk becomes tape”
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

5. It’s not Just the Interface!
A drive,
is a drive,
is a drive.
Or is it ?
Cost
Reliability
Scalability
Performance
Data Integrity
Desktop
7,200 rpm
ATA/SATA
Power Consumption
Enterprise
15,000 rpm
SCSI/FC
System Architecture
What’s important
to the Application ?
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

6. PS Drive RV Operating Range
RVI (max rms)
Cabinet Compare
w/Cheetah 10K.6 - Seek Data Only 5 10 15 20 25 30 35 40 45 50 1 2 3 4 6 7 8 9 11 12 13 14 16 17 18 19 21 22 23 24 26 27 28 29 31 32 33
Cabinet/Vendor
rads/sec
(rms)
---
Bars represent range of min to max values
Abnormal Range
37 Rad/s**2
Normal Range
21 Rad/s**2
Average of all samples for this cabinet
PS Drive RV Operating Range
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

7. D. Petravick -- Office of Science Data Management Workshop
Application -- Backup
Current:
Large permanent store people and backup community share tape as a media
Talks by COPAN, Kai Li (Princeton)
Backup community is interested in disk.
Accelerated backup
Diminishes the role of removable media
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

8. Application Permanent Store
High Energy Physics sites currently have ~2PB.
Ingest rate to permanent stores are ~100 TB/month
Permanent stores are not necessarily archives.
Loss rate per replication
About 1/million
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

9. Large Permanent Stores
Currently implemented on tape.
Requirements beyond naïve cost, capacity
Security requirements, accident
Full understanding of errors in the systems
Issue of continuously ingesting materials.
Archival quality of personal disk
Not only Disk BER, block-level logic errors
FNAL commodity disk/ Linux buffering experience
Archival disk format should be
Robust Standard
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

10. Application -- Buffering
secure community v.s. high perf/science community.
Commodity v.s. enterprise approach
Middleware v.s. kernal
Questions of if posix access semantics are sufficient.
Extensions, if any were not clear
12/31/2018
D. Petravick -- Office of Science Data Management Workshop

11. Tentative, Personal Gap Analysis from DLSS.
Disks as a technology
Big Science buffers are not a market center for personal disks
Analogous to good cluster building?
In the limit COTS !=> JIT?
Access
Evident need to understand if POSIX semantics are sufficient.
Extensions, common basis for them were not clear
Could be explored
Permanent Store, as we know it.
There is Potential for fiducially permanent store
The kind a program manager would trust
Work needed, not explicitly supported in the market today.
Backup
Is increasingly specialized.
12/31/2018
D. Petravick -- Office of Science Data Management Workshop