sco-notes

Linux磁盘测试的源代码,测试磁盘的读写性能

August 18th, 1999

	SCO UnixWare 7.1 Specific Notes:
	--------------------------------
     o	Device names are:

	/dev/cdrom/cdromN		CD-ROM devices.
	/dev/{dsk,rdsk}/cNbNtNdNXN	Disk devices.
	/dev/fd/*			Floppy diskettes.
	/dev/mc/mcN			Medium changers.
	/dev/rmt/{ctapeN,ntapeN,...}	Tape devices.
   
  SCSI and non-SCSI disks
  
   Disk device filenames have either of the two following forms:
   /dev/[r]dsk/cCbBtTdDsS
   /dev/[r]dsk/cCbBtTdDpP
   
   [r]dsk
          /rdsk denotes a raw (character) device; /dsk indicates a block
          device.
   cC
          C is the occurrence of the host adapter board or IDE controller
          in the system (that is, card number). C can range from 0 to 31.
   bB
          B is the HBA bus number, ranging from 0 to 7 (dependent on the
          add-on adapter). This is always 0 for IDE disks.
   tT
          T is the SCSI target controller number (ID). The value of T can
          range from 0 to 31. The first IDE disk is target 0, and the
          second is target 1.
   dD
          D is the logical unit number of the disk device, ranging from 0
          to 31. This is always 0 for IDE disks.
   sS
          S is the disk slice number, ranging from 0 to b7 (hex).
   pP
          P is the fdisk(1M) partition number. P can range from 0 to 4,
          to specify an entry in the fdisk partition table. The p0 node
          corresponds to the whole disk, the p1 to p4 nodes correspond to
          partitions as they are displayed by the fdisk command.
          
	Note:  Device names are NOT zero based, they start at '1'!

     o	Manual pages for reference:

	sdi (7)		- Storage Device Interface subsystem
	mc01 (7)	- Storage Device Interface (SDI) medium changer target driver
	sc01 (7)	- CD-ROM Target Driver
	sd01 (7)	- Storage Device Interface (SDI) disk target driver
	st01 (7)	- Storage Device Interface (SDI) tape target driver
	sw01 (7)	- Storage Device Interface (SDI) WORM Target Driver
	sdiconfig (1M)	- determine which SDI disk, tape, and SCSI controllers are present
	sdi_timeout	- query or change SDI device timeout tunables and more
	fd (7)		- floppy disk driver
	disk (7)	- disk device file
	tape (1)	- magnetic tape maintenance
	tape (7)	- tape devices
	tapecntl (1)	- tape control for tape device
	mt (1)		- portable tape device control
	mccntl (1M)	- medium changer control

	Note: 'mt' on SCO is very limited (only 2 commands), so use
		'tape' and/or 'tapecntl' utilities.

	'mccntl' provides medium changer support.
	( and I didn't have to load a CLC kit :-)

     o	Use 'sdiconfig' to list SCSI devices found at boot:

	sco# sdiconfig -l
	0:0,7,0: HBA     : (cpqsc,1) Compaq SCSI-2
	  0,3,0: TAPE    : HP      C1557A          U709
	  0,3,1: CHANGER : HP      C1557A          U709
	  0,8,0: DISK    : COMPAQ  DDRS-34560W     S97A
	2:0,7,0: HBA     : (cpqsc,2) Compaq SCSI-2
	  0,3,0: CDROM   : DEC     RRD42   (C) DEC 4.5d
	sco# 

     o	Kernel messages are located in /var/adm/log/osmlog

     o	Default file system is VERITAS File System.  References:

	diskadd(1M)	- disk set up utility
	disksetup(1M)	- disk set up utility 
	emergency_disk(1M) - create emergency recovery diskettes
	fdisk (1M)	- create or modify hard disk partition table
	fstyp (1M)	- determine filesystem type (generic)
	fsadm_vxfs(1M)	- resize or reorganize a VERITAS File System
	labelit (1M)	- provide labels for VERITAS File Systems
	mkfs (1M)	- construct a VERITAS File System
	mount (1M)	- mount a VERITAS File System
	edvtoc (1M)	- VTOC (Volume Table of Contents) editing utility
	prtvtoc (1M)	- disk information display utility
	vtoc (7)	- fdisk disk partition and UnixWare slices

sco# prtvtoc /dev/rdsk/c0b0t8d0s0
slice 0:        DISK            permissions:    VALID UNMOUNTABLE 
        starting sector:        63 (cyl 0)              length: 8369802 (521.00 cyls)
slice 1:        ROOT            permissions:    VALID 
        starting sector:        498015 (cyl 31)         length: 7743330 (482.00 cyls)
slice 2:        SWAP            permissions:    VALID UNMOUNTABLE 
        starting sector:        64260 (cyl 4)           length: 433755 (27.00 cyls)
slice 7:        BOOT            permissions:    VALID UNMOUNTABLE 
        starting sector:        63 (cyl 0)              length: 34 (0.00 cyls)
slice 8:        ALT SEC/TRK     permissions:    VALID UNMOUNTABLE 
        starting sector:        97 (cyl 0)              length: 15968 (0.99 cyls)
slice 10:       STAND           permissions:    VALID 
        starting sector:        16065 (cyl 1)           length: 48195 (3.00 cyls)
slice 15:       VOLPRIVATE      permissions:    VALID UNMOUNTABLE 
        starting sector:        8241345 (cyl 513)               length: 16065 (1.00 cyls)
sco# 

	Notes:
	- A disk 'slice' is a contiguous section of a partition.
	- There's a maximum of 4 partitions and 184 slices per partition.
	- There's a maximum of 256 slices (minor numbers) per disk.
	- Partition 0 is the entire disk.  See disk(7) for more info.
	- Slice 0 is the whole partition.  See vtoc(7) for other slices.
	- You cannot do I/O to a disk unless a partition exists.
	  Accessing non-existant partitions results in "No such device",
	  and accessing non-existant slices results in an EOF:

	sco# dt if=/dev/rdsk/c2b0t2d0p0 bs=64k pattern=0 limit=1g
	dt: open -> dt: '/dev/rdsk/c2b0t2d0p0' - No such device

	- You can use a non-existant slice to access the disk with 'scu':

	sco# scu -f /dev/rdsk/c2b0t2d0p0
	scu: Unable to open device '/dev/rdsk/c2b0t2d0p0', errno = 19 - No such device
	sco# scu -f /dev/rdsk/c2b0t2d0s0
	scu> sho nexus
	Device: HC0183172A, Bus: 2, Target: 2, Lun: 0, Type: Direct Access
	scu> 

     o	POSIX asynchronous I/O (AIO) is fully supported (yea!).

     o	Tape I/O requests must be in length a multiple of the tape block
	length.  The default value is 512 bytes.

     o	The largest tape block size appears to be 60KB.  Anything larger
	returns "Invalid argument" (EINVAL).


	Known Problems:
	---------------
     o	I'm unable to write/read more than 2Gbytes with AIO enabled:

	sco% dt of=/dev/rmt/ctape1 bs=32k limit=4g pattern=iot aios=10     
	dt: 'aio_return' - No such device or address
	dt: Error number 1 occurred on Sat Aug  7 14:22:29 1999
	Total Statistics:
	     Output device/file name: /dev/rmt/ctape1
	    Data pattern string used: 'IOT Pattern'
	     Total records processed: 65536 @ 32768 bytes/record (32.000 Kbytes)
	     Total bytes transferred: 2147483648 (2097152.000 Kbytes, 2048.000 Mbytes)
	      Average transfer rates: 1275425 bytes/sec, 1245.532 Kbytes/sec
	     Asynchronous I/O's used: 10
	     Number I/O's per second: 38.923
	      Total passes completed: 0/1
	       Total errors detected: 1/1
	          Total elapsed time: 28m03.74s
	           Total system time: 00m11.88s
	             Total user time: 00m31.30s
	               Starting time: Sat Aug  7 13:55:01 1999
	                 Ending time: Sat Aug  7 14:23:05 1999

	sco% 

     o	There's also a problem, or anomoly, with the way UnixWare handles the
	end of media condition.  Here ENXIO is returned, instead of ENOSPC
	which is what 'dt' expects.  Note:  The aio_read() reference page
	does not describe the error returned at EOM, and does not list either
	of these errno codes.  As you can see, non-AIO works just fine :-)

	sco# dt if=/dev/rdsk/c0b0t8d0s0 bs=64k disable=compare aios=8
	dt: WARNING: Record #65390, attempted to read 65536 bytes, read only 5120 bytes.
	dt: 'aio_return' - No such device or address
	dt: Error number 1 occurred on Tue Aug 10 19:51:48 1999
	Total Statistics:
	      Input device/file name: /dev/rdsk/c0b0t8d0s0 (device type=disk)
	           Data pattern read: 0x39c39c39 (data compare disabled)
	     Total records processed: 65389 @ 65536 bytes/record, 1 partial
	     Total bytes transferred: 4285338624 (4184901.000 Kbytes, 4086.817 Mbytes)
	      Average transfer rates: 3538619 bytes/sec, 3455.683 Kbytes/sec
	     Asynchronous I/O's used: 8
	     Number I/O's per second: 53.996
	      Total passes completed: 0/1
	       Total errors detected: 1/1
	          Total elapsed time: 20m11.02s
	           Total system time: 00m11.57s
	             Total user time: 00m03.54s
	               Starting time: Tue Aug 10 19:31:37 1999
	                 Ending time: Tue Aug 10 19:51:48 1999

	sco# 
	sco# dt if=/dev/rdsk/c0b0t8d0s0 bs=64k disable=compare       
	dt: WARNING: Record #65390, attempted to read 65536 bytes, read only 5120 bytes.
	Total Statistics:
	      Input device/file name: /dev/rdsk/c0b0t8d0s0 (device type=disk)
	           Data pattern read: 0x39c39c39 (data compare disabled)
	     Total records processed: 65389 @ 65536 bytes/record, 1 partial
	     Total bytes transferred: 4285338624 (4184901.000 Kbytes, 4086.817 Mbytes)
	      Average transfer rates: 3538064 bytes/sec, 3455.141 Kbytes/sec
	     Number I/O's per second: 53.987
	      Total passes completed: 1/1
	       Total errors detected: 0/1
	          Total elapsed time: 20m11.21s
	           Total system time: 00m06.67s
	             Total user time: 00m00.24s
	               Starting time: Wed Aug 11 09:08:32 1999
	                 Ending time: Wed Aug 11 09:28:43 1999

	sco#   

     o	There's a long delay when closing files after the read pass,
	which causes the total transfer rates to be lower than expected:

	sco% dt of=dt.data bs=32k limit=50m pattern=iot                       
	Write Statistics:
	     Total records processed: 1600 @ 32768 bytes/record (32.000 Kbytes)
	     Total bytes transferred: 52428800 (51200.000 Kbytes, 50.000 Mbytes)
	      Average transfer rates: 1720670 bytes/sec, 1680.341 Kbytes/sec
	     Number I/O's per second: 52.511
	      Total passes completed: 0/1
	       Total errors detected: 0/1
	          Total elapsed time: 00m30.47s
	           Total system time: 00m00.48s
	             Total user time: 00m00.67s

	Read Statistics:
	     Total records processed: 1600 @ 32768 bytes/record (32.000 Kbytes)
	     Total bytes transferred: 52428800 (51200.000 Kbytes, 50.000 Mbytes)
	      Average transfer rates: 10043831 bytes/sec, 9808.429 Kbytes/sec
	     Number I/O's per second: 306.513
	      Total passes completed: 1/1
	       Total errors detected: 0/1
	          Total elapsed time: 00m05.22s
	           Total system time: 00m00.37s
	             Total user time: 00m02.17s

	Total Statistics:
	     Output device/file name: dt.data
	    Data pattern string used: 'IOT Pattern'
	     Total records processed: 3200 @ 32768 bytes/record (32.000 Kbytes)
	     Total bytes transferred: 104857600 (102400.000 Kbytes, 100.000 Mbytes)
	      Average transfer rates: 2108538 bytes/sec, 2059.119 Kbytes/sec
	     Number I/O's per second: 64.347
	      Total passes completed: 1/1
	       Total errors detected: 0/1
	          Total elapsed time: 00m49.73s
	           Total system time: 00m00.87s
	             Total user time: 00m02.84s
	               Starting time: Sat Aug  7 14:36:14 1999
	                 Ending time: Sat Aug  7 14:37:04 1999

	sco%