This document describes how to plan for and measure Input Output Operations per
second (IOPs) when commissioning disk storage to store Deduplication Database.
Deduplication database disk volume stores a multi-threaded high performance
database that contains block signatures and plays a critical role in deduplication
enabled backups and DASH copies. Deduplication database needs to be on a fast disk
for optimal backup and DASH copy performance.
The following section explains the use of Iometer which is a widely used
industry standard tool for measuring IOPs. Using IOPs rating provides a standard and simplified
way to commission storage without having to understand and use proprietary tools.
After configuring storage volumes, run Iometer to confirm the volumes provide
recommended IOPs as described in the below table, that is, with 1 worker thread:
320+ IOPs and with 8 worker threads: 1000+ IOPs. As long as the storage volumes
can provide rated IOPs, the actual physical configuration behind the volumes is
immaterial. Example: If a RAID 6 configured volume consistently provides the same
IOPs as a RAID 0 configuration, it is OK to use RAID 6 configured volume.
Note that the IOPs ratings are per DDB volume. If multiple MediaAgents use
SAN attached LUNs belonging to the same disk array, make sure to test IOPs
ratings concurrently on all MediaAgents by running IoMeter in parallel.
If the physical spindles behind the volume are shared between multiple volumes,
it is important to make sure the load on the underlying physical disks remains the
same as at the time of IoMeter testing. Increase in load on the shared disks may
result in degraded performance.
Deduplication database must be hosted on the volumes that meets the below IOPs
requirement.
Node Type
RAM
Suggested DDB Volume Size
IOPs With Single worker thread
IOPs With 8 Worker Threads
Estimated Front End Size*
Estimated Backend Size**
Example Configurations
Extra Large
32-64 GB
800 GB - 1 TB
IOPs exhibited by SSD or Flash based storage devices
Ensure to run the Iometer test on the complete raw
disk.
If you wish to run the Iometer on a volume which has the data,
then make sure to copy the data on a different location before
performing the test. This is to avoid the data loss issue. Once the test
is complete you can copy back the data to old location.
3.
Stop all the services on the MediaAgent on which the
IOPS need to be tested.
Perform the following steps to stop the
services:
Click the Start button on the Windows task bar and then click
All Programs.
Navigate to bull | Calypso
and click Service Control Manager.
Right-click All Services and click Stop to stop
all services.
4.
Make sure that there is no SIDB.exe process running on
the MediaAgent.
For Windows, verify from Windows Task Manager - Processes
tab.
For Unix/Linux, run ps command.
5.
Copy all the data from the volume that needs to be
tested to a temporary folder.
Make sure that permission on the
files/folders are also copied.
Worker thread is an entity that runs the test defined under Access Specification
Tab of IoMeter UI. Multiple worker threads run the tests in parallel to test
concurrent performance.
Use the following steps to run Iometer using single worker thread:
7.
Right-click Iometer and click Run as Administrator.
8.
The Iometer dialog box will appear.
9.
Click on the name of the computer available in the Topology
panel on the left side of the window.
The available disk drives will appear
in the Disk Targets tab.
IoMeter, on startup, creates one Manager with multiple worker threads.
Leave one worker thread and delete remaining worker threads by selecting
the worker thread and clicking the Disconnect Selected Worker or
Manager button.
It is recommended to run Iometer on the physical disk that
represents the storage volume for which IOPs need to be measured.
Iometer will allow physical disks to be selected only when there
are no volumes on the disk.
10.
In the Disk Targets tab, select a disk to use in
the test.
Values for Maximum Disk Size and Starting Disk Sector
should be set to default, that is 0, to test the complete disk
or volume.
In the figure, blue disk icon represent
physical drives which has no partitions on them.
In the following figure, PHYSICALDRIVE:2 is the disk selected
for the test.
To test the disk available on linux machine, Iometer requires two components,
Iometer UI and Dynamo.
The Iometer UI is run on Windows host. It is possible to load the Dynamo workload
generator on another host (linux host). In the following case, the Linux host running
Dynamo is the machine under test, and the Windows host running the Iometer UI is
just reporting the numbers.
1.
To perform Iometer test on linux machine two hosts are
required:
Windows host that runs Iometer UI
The Linux MediaAgent that runs dynamo to test the disks.
For installation instructions, refer to Iometer documentation on Iometer
website.
2.
After installation, verify network connectivity between
the two machines, make sure both the machine can ping each other. Run dynamo
on linux MediaAgent with two parameters:
-i -- Indicates the IP address of Windows host running Iometer
UI
-m -- Indicates the IP address of Linux host
In the figure below, 100.10.100.12 IP address specified by –I parameter
is the IP address of Windows host and IP address 100.10.100.23 specified
by –m is that of linux host.
3.
After running dynamo, run Iometer with administrator privileges
on Windows host.
