scsidisktest(1m)scsidisktest(1m)NAMEscsidisktest - finds and reallocates bad blocks on SCSI and Fibre Channel
Disks
SYNOPSISscsidisktest [-V (verbose)] [-x (Expert Mode)] [-R (Read Test)] [-W
(Write Test)] [-C (Write-Read-Compare Test)] [-n <No. of Times to run the
Test>] [-s <Starting Block>] [-t <Total No. of Blocks to test>] [-z <Max
No. of Blocks transferred per command>] [-S (Sequential Pattern)] [-B
(Butterfly Pattern)] [-P (Display P List)] [-G (Display G List)] [-L
(Show Defective Block Count)] -d DEVICE
DESCRIPTIONscsidisktest is an interactive utility to analyze the disk surface of
SCSI devices accessed using the SGI SCSI subsystem. It finds and
reallocates bad blocks on the disk. It can also be used to display the
Disk Defect Lists (P List and G list).
OPTIONS
-V Verbose Mode
In this mode scsidisktest displays the block numbers of the blocks
being tested while the test is in progress.
-x Expert Mode
This mode allows the testing process without being interrupted for
confirmation.
-R Read Test
During this test,the SCSI Read(10) Command is used to read data
blocks from the disk (without any retries).
-W Write Test
During this test, a random byte pattern is written to the disk using
the SCSI Write(10) Command (without any retries).
-C Write-Read-Compare Test
During this test, a random byte pattern is written to the disk using
the SCSI Write(10) Command (without any retries) and that pattern is
read from the disk using the SCSI Read(10) Command (without any
retries). The pattern read, is checked against the pattern written
earlier to check for any discrepancies.
-n <No. of Times to run the test>
The test can be run for multiple times depending on the value given
here.
-s <Starting Block>
This specifies the starting block of the chunk of blocks being
tested.
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scsidisktest(1m)scsidisktest(1m)-t <Total No. of Blocks to Test>
This specifies the total no. of blocks being tested.
If the -s <Starting Block> and -t <Total No. of Blocks> choices are NOT
specified, then the test is carried out on the entire disk under
consideration (Recommended).
-z <Max No. of Blocks transferred per command>
This specifies the maximum data transfer size during the SCSI
Read(10), Write(10) commands. If not specified, a maximum of 256
blocks are transferred in every Read(10), Write(10) command during
the test.
-S Sequential Pattern
In this pattern the disk sectors are scanned sequentially.
-B Butterfly Pattern
In this pattern the user scans the disk surface alternately from the
extremes of the block length being scanned.
-P Display P List
Display the defective blocks in the P List in the Physical Sector
Format.
-G Display G List
Display the defective blocks in the G List in the Physical Sector
Format.
-L Show Defective Block Count
Display the total number of defective blocks on the disk. This
number includes the blocks in all Defect Lists.
Interactive Mode Menus
Scan Modes (Read | Write | Write-Read-Compare)
In the Read Mode the user performs a SCSI Read(10) (with no retries)
on the disk. In the Write Mode the user writes a random byte
pattern on the disk using the SCSI Write(10) command (with no
retries). In the Write-Read-Compare Mode the user writes a random
byte pattern on the disk using the SCSI Write(10) command (with no
retries), performs a SCSI Read(10) (with no retries) and then
compares the bytes read, with the bytes written for any
discrepancies.
The Write-Read-Compare Mode performs the most exhaustive scan of the disk
surface.
Scan Pattern (Butterfly | Random | Sequential)
In the Butterfly Pattern the user scans the disk surface alternately
from the extremes of the block length being scanned. In the Random
Pattern the user scans any random block in the block length under
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consideration. In the Sequential Pattern the user scans the disk
surface sequentially.
The disk surface is normally scanned in chunks of 256 blocks. If an
error is detected, the chunk causing the error is scanned again, 1 block
at a time to find the block causing the error. That block is then
reallocated. If there is no space on the disk to reallocate that block,
a corresponding error message is displayed.
Hardware Defect List (P List | G List)
P (Primary Defect Type) List : P type flawed sectors are identified
at the time of shipment in a list of defects (permanent flaws)
supplied by the manufacturer and stored on the disc in an area that
is not directly accessible by the user. (This list may be referred
to as an ETF List). This defect list is not modified or changed by
the disc drive (or initiator) after shipment.
G (Growth Defect Type) List : G type flawed sectors contain medium
flaws and have been reallocated as a result of receiving a Reassign
Blocks command, or certification defects (C type) reallocated during
a previous Format Unit command, or Data Defects (D type) reallocated
during a previous Format Unit command or defects that have been
automatically reallocated by the drive. This (G) list is recorded on
the disc drive media and may be referenced for the current (and
subsequent) Format Unit commands. This (G) list does not include the
Primary (P) list of defects.
List Display Format (Bytes From Index | Physical Sector) :
Each defect descriptor for the Bytes from Index format specifies the
beginning of an eight bit (1 byte) defect location on the medium.
Each defect descriptor is comprised of the cylinder number of the
defect, the head number of the defect and the number of bytes from
Index to the defect location. Each defect descriptor for the
Physical Sector format specifies a sector size defect location
comprised of the cylinder number of the defect, the head number of
the defect and the defect sector number.
Add Bad Block to the Hardware Defect List:
This options allow the user to add a defective block to the G List
using the SCSI Reassign Blocks Command.More information about the
Reassign Blocks command can be found in the SCSI-3 Block Commands
(SBC) document.
EXAMPLES
Under Irix, the device name must correspond to the 'sc' device.
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scsidisktest(1m)scsidisktest(1m)
o scsidisktest-d /dev/scsi/sc9d70l0
In the interactive mode, scsidisktest has to be invoked without the
-RWCSBnstx options (as shown above).
o scsidisktest-V -d /dev/scsi/sc9d70l0
When invoked with the (-V) Verbose option, scsidisktest prints out the
block numbers being tested while carrying out the test (in the
interactive mode).
o scsidisktest-C -B -n 2 -x -d /dev/scsi/sc9d70l0
In the non-interactive mode, scsidisktest is invoked as shown above.
This causes scsidisktest to perform a (-C) Write-Read-Compare test on the
entire disk sc9d70l0 by scanning it in a (-B) Butterfly pattern, (-n) 2
times.
o scsidisktest-C -B -n 2 -s 100 -t 100000 -x -d /dev/scsi/sc9d70l0
This invocation in the non-interactive mode, causes scsidisktest to
perform a (-C) Write-Read-Compare test on (-t)100000 sectors of the disk
sc9d70l0 starting from (-s) sector 100, by scanning it in a (-B)
Butterfly pattern, (-n) 2 times.
o scsidisktest-V -C -B -n 2 -s 100 -t 100000 -x -d /dev/scsi/sc9d70l0
This invocation in the non-interactive mode, causes scsidisktest to
perform a (-C) Write-Read-Compare test on (-t)100000 sectors of the disk
sc9d70l0 starting from (-s) sector 100, by scanning it in a (-B)
Butterfly pattern, (-n) 2 times. Due to the (-V) Verbose option,
scsidisktest also prints out block numbers while the blocks are being
tested.
o scsidisktest-P -d /dev/scsi/sc9d70l0
This invocation causes scsidisktest to display the defective blocks in
the P list for disk sc9d70l0 in the Physical Sector Format.
o scsidisktest-L -d /dev/scsi/sc9d70l0
This invocation causes scsidisktest to display the total number of
defective blocks on the disk.
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scsidisktest(1m)scsidisktest(1m)FILES
/dev/scsi/sc*d*l* - the generic 'sc' device under Irix.
SEE ALSOscsicontrol(1M), scsiha(1M), scsimodepage(1M), scsidiskformat(1M).
NOTE
This command is normally usable only by the superuser, because the
standard permissions of the devices restrict access to other users.
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