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- NetFRAME Systems Inc.
-
-
-
- DX
- A Disk Exerciser for NetWare 386 (TM)
-
-
- WHAT IS DX?
-
- DX (Disk eXerciser) is a portable performance analysis tool. It can be run
- on systems that run Novell's NetWare 386 (TM). DX was developed at
- NetFRAME Systems Inc., in response to a need to analyze and characterize
- physical disk IO performance, without file system caching effects,
- over a variety of operating conditions.
- DX is a NetWare Loadable Module, or NLM. It can be loaded and run from
- the operator's console of a NetWare 386 system. It can provide a variety
- of system configuration options in examining physical disk IO throughput.
- It is portable and easy to use, providing users a variety of reproducible
- conditions.
-
- BEFORE YOU START
-
- DX is provided on either a 3.5" or 5.25" floppy, along with this file. Its
- filename is DX.NLM. You must have a system capable of running NetWare 386,
- a copy of NetWare 386, Rev 3.0 or higher, and at least one hard disk.
- DX should not be run on any disk that has volume SYS mounted.
- This is because DX can do destructive writes on any location in a NetWare
- partition. In general, if you wish to run DX on a system with useful data
- on the disks, you must backup all of the data before running DX, and later
- restore the data.
- DX can only be run on disks or drives that have a NetWare partition on
- them. If you wish to run DX on a disk that doesn't have a NetWare partition,
- you must create one using the INSTALL utility provided with NetWare. See
- the appropriate Novell documentation to use this utility.
-
- HOW TO RUN DX
-
- First, bring up NetWare 386 on your system. Do not mount SYS or any other
- volume(s). Be sure to load the appropriate disk driver(s) to exercise your
- disks. Other NLMs could be loaded (e.g. INSTALL, MONITOR) as required, but
- they are not necessary to run DX. Be sure all useful data on your drives
- are backed up. Either download the dx.nlm into your DOS partition, copy
- into the system directory of the Netware 386 volume, or load from a floppy
- drive. At the operator's console, type LOAD DX. DX will clear the screen
- and ask a series of questions:
-
- 1. Exerciser Access Pattern [S=Sequential R=Random]? S
-
- The answer to this question determines how DX will access the disk-
- sequentially or at random. In sequential access, DX will start requesting
- data at the beginning of the drive, and increment the block address for
- each successive operation. When it reaches the end of the drive, it will
- wrap around and start at 0 again. In random access, a random number
- generator with a uniform distribution is used to generate a block address
- ranging from the beginning to the end of the drive.
- Sequential access tests measure a system's capacity to read or write
- large files. Random access tests, with uniform distribution, are useful in
- examining a system's ability to handle heavy IO demands with poor disk locality.
-
- 2. Exerciser test type [R=Read W=Write]? R
-
- The answer to this question determines if DX will perform all reads or all
- writes for the duration of the test. Note that data
- read from drives by DX is discarded. Data written to drives is not
- subsequently verified by this program. Use of the NetWare parameter "Enable
- Disk Read After Write Verify" can be used to provide write verify performance
- measurement, in concert with DX's write option. However, not all disk
- drivers implement this feature, even though the option is turned on. Use care
- in examining the results before assuming the feature is supported. There
- should be a noticeable drop in write throughput when write verify is on and
- supported. The default operation is Read.
-
- 3. Number of kilo bytes <KB> per IO [1-60]? 8
-
- This answer instructs DX on how big each physical IO should be--1 to 60KB
- long. The default is 8KB per IO. Small IO operations (1KB) can give an
- indication of the maximum IOs per seconds a controller/drive(s) combination
- can sustain. Medium size IOs can give an indication of how a common NetWare
- system may perform (many NetWare systems are configured with 4-16KB
- cache buffer sizes, which corresponds to the blocksize of the
- disk request). Large IOs can give an indication of the data throughput that
- is sustainable, since large IOs usually minimize controller to drive protocol
- overheads.
-
- 4. Number of concurrent IO to queue per drive [1-64]? 3
-
- DX is able to build and maintain a queue of requests for each drive before
- calling the disk driver to act on those requests. This number lets DX know
- how deep to keep this queue. This feature is useful for intelligent
- drivers and/or controllers that are capable of issuing multiple IOs,
- for elevator algorithms that take advantage of sorts to improve disk access
- time, etc. The default queue depth is 3.
-
- 5. Screen Update Interval in seconds [1-60]? 5
-
- This tells DX how often to calculate and display statistics on the console.
- The default is 5 seconds.
-
- 6. Exercise Generic Drive 1-0-0? y
-
- For each drive in the system with a NetWare partition, DX will ask if you want
- to include that drive in the test. This is useful for excluding certain
- drives with data you want untouched, or to characterize your system on a disk
- by disk, controller by controller, or system wide basis. The default answer
- to these questions is yes, so care is required. The format of the drive
- number is Controller number, Device ID, LUN. Also note that the search for
- disk drives will end when DX encounters a drive without a NetWare partition.
-
- THE DX DISPLAY
-
- After questioning you about all the drives with NetWare partitions, DX will
- clear the screen and start exercising the disk(s) you specified in the manner
- you requested. After the screen update interval, it will display the statistics
- it has gathered so far. Here is a sample display:
-
- --------------------------------------------------------------------------------
- NetFRAME Disk Test: Sequential Read 32KB/IO with 3 IOs queued Page 1 of 1
- Disk KB/sec. IOs/sec Ave. KB/s Total IOs Errors
- Generic Drive 1-0-0 812 25 752 9976 0
-
- Aggregate Disk Performance 812 25 752 9976 0
- Server Utilization 7%
- Q to quit or page number to view
-
-
- --------------------------------------------------------------------------------
- NOTE: The numbers supplied above are provided for reference only and do not
- reflect the physical disk performance of any system.
-
- The top line identifies DX, the type of test it is running, and the page
- being displayed. DX can display statistics on very large systems. It has been
- tested on a system with 32 drives. Each page of a DX display has statistics
- for up to 16 drives. Aggregate statistics are shown on every page.
- To display the information on any page, type in the page number on the
- keyboard at the operator's console. After the next display interval, that page
- will be shown until a new page number is typed, or you exit DX.
- To exit DX, type "q" (the letter only). DX will ask you if you really want
- to exit. Type y or n at the prompt, which will appear at the bottom line of
- the display. The default is yes.
- You may also do other things while DX is running. You may use the
- <ALT-EXC> or <CTL-ESC> key combinations to cycle through any other NLMs you
- have running, or to the console. However, other activities on the system
- could perturb your results.
- The second line consists of column heading, to identify which statistics
- are collected in that column. The Disk column identifies which drive is
- being tested. The KB/sec column identifies how many kilobytes per second were
- transferred during the last display interval. The IOs/sec column shows how
- many physical IOs per second were completed during the last display interval.
- The AVE. KB/s column displays the average data transfer rate since the beginning
- of the test. The Total IOs column shows the number of completed physical IOs
- since the beginning of the test. The Errors column details the reported
- physical IO errors since the beginning of the test.
- DX then displays statistics for up to 16 drives per page. It also
- sums the statistics for all tested drives on the AGGREGATE Disk Performance
- line. These statistics are shown on all pages. Finally, the CPU utilization
- for the server is displayed. CPU utilization is the percentage of processor
- time used marginally to process the benchmark results and mostly to execute
- the disk IO requests. The remainder (unused CPU cycles) is the processor time
- available to perform other functions on the system.
-
-
- CAVEATS
-
- To change test parameters, you must quit the program and reload it.
-
- There is no explicit way to capture DX displays to a file or files.
-
- DX only displays information about completed IOs.
-
- DX has no provision for gathering statistics on a per controller basis.
-
- DX has no provision for doing 512 byte (a common disk sector size) IOs.
-
- DX has no provision for operating only on part of a NetWare partition.
-
- DX tests can be destructive to data.
-
- DX is not a capacity planning tool and does not predict total system demands
- for particular customer environments.
-
- When running both DX and NX, be sure to load both NLMs before starting
- either. If you don't, server CPU utilization percentages will be
- in error. This is due to the way NetWare 386 handles the loading of NLMs
- in relation to server CPU utilization.
-
- DX is provided as is, with no warranty, explicit or implied. NetFRAME Systems
- Inc. assumes no responsibility for any information provided by DX, nor any
- effects, direct or indirect, on your system. DX has been tested on NetFRAME
- systems, and on a limited number of ISA, EISA, and MCA systems, and has shown
- no deleterious side effects to systems under test. However, DX may exhibit
- side effects on your system.
-
- TRADEMARKS
-
- Novell, NetWare, NetWare 386, NetFRAME, and NetFRAME Systems, are the trademarks
- of Novell, Inc. and NetFRAME Systems Inc.
-
- (c) 1990 NetFRAME Systems Inc., 1545 Barbar Lane, Milpitas, CA 95035