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Wednesday, October 21, 2015

The right I/O tool to test disk performance - VDBENCH

Thanks to Henk Vandenbergh for developing this great tool.

Simple to use and a lot of resources and options. Works in almost all OS:

This example below was used in my mac laptop.


pportugal@dhcp-adc-twvpn-3-vpnpool-10-154-105-192 [] /Users/pportugal/Downloads/vdbench50403> ./vdbench -t


Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Vdbench distribution: vdbench50403 Mon May 04  9:22:37 MDT 2015
For documentation, see 'vdbench.pdf'.

13:13:52.968 Created output directory '/Users/pportugal/Downloads/vdbench50403/output'
13:13:53.137 input argument scanned: '-f/var/folders/r5/v8vgh1v10z52rfn4b4nlsd8h0000gp/T/parmfile'
13:13:53.305 Starting slave: /Users/pportugal/Downloads/vdbench50403/vdbench SlaveJvm -m localhost -n localhost-10-151021-13.13.52.936 -l localhost-0 -p 5570
13:13:53.698 All slaves are now connected
13:13:53.805 Vdbench will attempt to expand a disk file if the requested file size is a multiple of 1mb
13:13:53.805 lun=/var/folders/r5/v8vgh1v10z52rfn4b4nlsd8h0000gp/T/quick_vdbench_test does not exist or is too small. host=localhost
13:13:55.002 Starting RD=SD_format; I/O rate: Uncontrolled MAX; elapsed=(none); For loops: threads=2 iorate=max
13:13:55.164 All sequential workloads on all slaves are done.
13:13:55.164 This triggers end of run inspite of possibly some non-sequential workloads that are still running.

Oct 21, 2015  interval        i/o   MB/sec   bytes   read     resp     read    write     resp     resp queue  cpu%  cpu%
                             rate  1024**2     i/o    pct     time     resp     resp      max   stddev depth sys+u   sys
13:13:56.088         1     320.00    40.00  131072   0.00    0.606    0.000    0.606   21.419    1.845   0.2   NaN   NaN
13:13:56.099   avg_1-1       0.00     0.00       0   0.00    0.000    0.000    0.000    0.000    0.000   0.0   NaN   NaN
13:13:57.001 Starting RD=rd1; I/O rate: 100; elapsed=5; For loops: None

Oct 21, 2015  interval        i/o   MB/sec   bytes   read     resp     read    write     resp     resp queue  cpu%  cpu%
                             rate  1024**2     i/o    pct     time     resp     resp      max   stddev depth sys+u   sys
13:13:58.011         1      74.00     0.07    1024  51.35    0.028    0.025    0.031    0.126    0.018   0.0   NaN   NaN
13:13:59.007         2     105.00     0.10    1024  53.33    0.029    0.025    0.033    0.073    0.013   0.0   NaN   NaN
13:14:00.007         3     105.00     0.10    1024  49.52    0.026    0.022    0.029    0.052    0.012   0.0   NaN   NaN
13:14:01.006         4     107.00     0.10    1024  51.40    0.026    0.023    0.029    0.067    0.013   0.0   NaN   NaN
13:14:02.022         5      96.00     0.09    1024  54.17    0.027    0.025    0.029    0.081    0.012   0.0   NaN   NaN
13:14:02.046   avg_2-5     103.25     0.10    1024  52.06    0.027    0.024    0.030    0.081    0.012   0.0   NaN   NaN
13:14:03.002 Vdbench execution completed successfully. Output directory: /Users/pportugal/Downloads/vdbench50403/output

pportugal@dhcp-adc-twvpn-3-vpnpool-10-154-105-192 [] /Users/pportugal/Downloads/vdbench50403>




Best Regards,
Paulo Portugal

Friday, October 16, 2015

Enabling New Flash Cache Compression on Exadata Cells

The flash cards F40 and F80 support flash cache compression and uncompressed tables for example can reach a 4 times compression ratio.

To enable compression follow these steps:

1-Flush all the flash cache in cell

 CellCLI> alter flashcache all flush

2-Drop the flashcache

CellCLI> drop flashcache all

3-Drop all flash log

  CellCLI> dorp flashlog all

4-Drop all cell flash cache disks

  CellCLI> drop celldisk all flashdisk

5-On Cell that you want to enable flash cache compression run:

CellCLI> alter cell flashCacheCompress = TRUE

6-Create cell disk with flash disks

  CellCLI> create celldisk all flashdisk

7-Create flash log

  CellCLI> create flashlog all

8-Finally create flashcache

  CellCLI> create flashcache all

Best Regards,
Paulo Portugal

ps: for X3 run
CellCLI> alter cell flashCacheCompX3Support = TRUE

Wednesday, October 14, 2015

Create Sparse Grid Disks on Exadata Virtualized

Exadata Virtualized is there and one very nice feature is the Sparse Grid Disks.

With SGD you can create a disk that allocate space dynamically. So you can have a virtual size can be much bigger than the actual physical size. 

Example of how to create a Sparse Grid Disk and Sparse Disk Group:

create griddisk S_GD1 ... virtualsize=100g;

create diskgroup ... S_DG1 'spare grid disks here'  ;


Best Regards,
Paulo Portugal