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Page 1 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Analyzing NFS Client Performance with IOzone Don CappsTom.

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Presentation on theme: "Page 1 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Analyzing NFS Client Performance with IOzone Don CappsTom."— Presentation transcript:

1 Page 1 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Analyzing NFS Client Performance with IOzone Don CappsTom McNeal Performance ArchitectIndependent Consultant HPTMCN Consulting 1

2 Page 2 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Benchmark Overview Characteristics of IOzone Activities

3 Page 3 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Load Generation File System I/O requests – File sizes vary from 64K to 512M – Record sizes vary from 4K to 16M – Each increase doubles previous size – Large file system calls supported System variants supported – Memory mapped files – fread(), fwrite() – pread(), pwrite()

4 Page 4 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Sequential Reads/Writes Reads & Rereads Writes & Rewrites Backwards sequential read Stride read – Uses constant intervals for sequential reads from beginning to end

5 Page 5 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Other Reads/Writes Randomized Reads/Writes Record Rewrite (from offset 0) fread() – Reads and Rereads – Serialized, Buffered & Blocked IO fwrite() – Writes and Rewrites – Serialized, Buffered & Blocked IO

6 Page 6 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Recommended Variants for NFS Clients All tests, all record sizes Commit time included in measurements IO targeted at mounted file – Unmount clears out caches between tests – Target file specified in mounted directory./iozone –azc –U /mnt/testdir –f /mnt/testdir/testfile

7 Page 7 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Benchmark Results Characteristics of IOzone Reports

8 Page 8 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Graphical Reports Generate Excel output text Named file has graphs and data – 3D Surface Charts for all tests – Includes text output used for graphs Standard output sent to log file – Generally useful for debugging problems./iozone –R -b exceloutput.xls > logfile

9 Page 9 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Surface Plot Graphs

10 Page 10 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Surface Plot Graphs II

11 Page 11 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE System & Network Variants Environmental Control and Interactions

12 Page 12 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE System Level Variations SMP Issues – Processor cache purges – Processor affinity (for a given # of cpus) – Lower bound of number of cpus Cache Management – CPU Cache size – CPU Cache line size -p, -P #, -l n, -S size, -L size

13 Page 13 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE System parameters Client BIOD Daemons Server NFSD Daemons Number of file system nodes – rnode/inode/vnode/file handles Directory Name Lookup Cache Network buffer sizes

14 Page 14 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE File System Variations O_SYNC file option for all tests File locking required for all IO Flush timings included – fsync() and fflush() Large file offsets – File system calls determined at make time – Alternate max file size may be specified -o, -W, -e, -g #

15 Page 15 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE File System Variations II Memory mapped file IO – mmap() interface – MS_ASYNC or MS_SYNC usage available Posix asynchronous IO -B, -D, -G, -H n, -k n

16 Page 16 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Network Variations UDP/TCP Protocol Client transfer sizes Network speed, duplex settings – Autonegotiation is often interesting IP issues – Jumbo frames with gigabit ethernet – Stream heads, Socket buffer sizes

17 Page 17 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Clustered Clients Managing and Measuring a Cluster

18 Page 18 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Client Specification Clients specified in a file Clients must be accessible – Remote shells enabled through.rhosts DNS ® IOzone revision or later Stonewalling helpful (removed by –x) -+m filename

19 Page 19 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Stonewalling Client tests initiated in tandem – All clients kept equally busy When one finishes, they all finish – Tests halted when the first client completes Emulates high performance parallel processing clusters – Beowulf clusters at LLNL, PNNL, Los Alamos

20 Page 20 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Summary Examples and References

21 Page 21 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Summary NFS Client measurement standard Gather standard data first – What is right for your client? Review Variations and Features – Review System, FS, and Network setup – Start tuning, playing, tuning, playing…../iozone –azcR –U /mnt/testdir –f /mnt/testdir/testfile \ -b exceloutput.xls > logfile

22 Page 22 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Rewrite Graph

23 Page 23 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Reread Graph

24 Page 24 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE Random Read Graph

25 Page 25 of NFS Industry Conference October 22-23, 2002 NFSNFS INDUSTRYINDUSTRY CONFERENCECONFERENCE References – Contains 8K vs. 32K Transfer Size graphs nfstestmatrix – Includes functional tests, destructive tests, and benchmarks for Linux systems – Linux Server performance review (late 2001)


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