Les fichiers spéciaux pour les sauvegardes

vendredi 3 juillet 2009
par  Jerome ROBERT
popularité : 5%

Les fichiers spéciaux pour les sauvegardes ....








Configuring DDS drives on HP S700 systems

Minor Numbers

Minor number format is 0x[BBB][T][L][D] where:
BBB =bus interface
201 = Core SCSI
4[S]0 = EISA SCSI ([S] = SLot number)
T = Target SCSI ID (ie. DDS drive address)
7 = invalid (reserved for host system)
L = Logical Unit Number
For tape drives this is normally set to zero. It may be set to 8 to access partition 1.
D = Device type specific configudation parameters
xxx0 = Automatically rewind on close
xxx1 = Do not rewind on close
xx0x = AT&T style close (not recommended)
xx1x = BSD style close (recommended)
00xx = Low Density
01xx = Meduim Density
10xx = High Density
11xx = Very High Density (enables data compression)
Note that there are three possible "density" selections. The main (and only) effect of density selection is in controlling data compression on writes. The driver controlls the data compression capability of the drive based on this field of the minor number.

Example: Make a device file for a drive on address 3, core SCSI, no rewind on close, BSD style close:
mknod /dev/rmt/3hcn c 121 0x20130F

See also: /etc/newconfig/90RelNotes/hpuxsystem (search for "121") which describes minor numbers for the 121 driver.

Recommended Filename Conventions

Format [Den][Part][Type][Rew]
= "l" for low density
= "m" for medium density
= "h" for high density
= "hc" for very high density (compression enabled)
= "" for partition zero.
= "p" for partition 1.
= "A" for AT&T style close
= "" for BSD style close
= "" with auto-rewind on close = "n" with no rewind on close

DDS and fbackup

Be sure to use sensible values in your fbackup configuration file or you might end up with poor performance. Here are some suggested values:
blocksperrecord          64
records                  64
checkpointfreq          512
readerprocesses           3
maxretries               5
retrylimit               5000000
maxvoluses               200
filesperfsm             1000
PHCO_4309 fixes some fbackup problems including PHCO_3924 fbackup hang during incremental backup.

fbackup and DDS2 and HP-UX9.XX

The performance of frecover in conjunction with DDS2 on pre-HP-UX10.00 systems is pathetic. This is because fbackup does not recognise the identity of the DDS2 drive and writes data in a format which does not support DDS fast search. The only way to work around this problem is to set the DIP switches on the underside of the drive to:
Bear in mind the following warnings:
  • The drive will now identify itself as a 35480A (a DDS1-DC drive). This can cause vast confusion when someone is figuring out what hardware is on a system.
  • The drive firmware to support this switch config is June 1994 or later.
  • This switch combination will not speed up data recovery off tapes written before this switch combo was set.
  • This problem is supposed to be fixed in HP-UX10.00.

C1553A Autochangers and S800 systems

The S800's driver (pre-HPUX 10.0) does not recognise C1553A as a valid product ID and wil refuse to talk to the drive. To fix this, the switches on the rear of the autochanger need to be set to 1234=0110 (0 = switch arm away from circuit board, 1 = switch arm close to circuit board) which causes the C1553A to identify itself as a C1533A. It should now talk to an S800.

Note: If you have set the drive switch settings to report HP35480A (as suggested for the "fbackup and DDS2" workaround) then there is no need to alter the autochanger switches since the HP35480A switch setting on the drive overrides the C1533A autochanger switch option.

Backing up with cpio

Use the -B option to get 5120 byte records otherwise performance will be appalling. Even using -B with higher speed DDS drives might not guarantee the best data rates. Piping thru 'dd' is one way around this:
cpio -Bxxxx | dd ibs=5120 obs=65536 of=/dev/rmt/3hcn

Configuring DDS drives on SUN systems

SCSI Address

SUN requires that the SCSI address of Tape devices be either 4 or 5. If the address is set to 4, the 'rst0' or 'nrst0' drivers are used. If the address is 5, 'rst1' or 'nrst1' is used.

Solaris 2.4 and later

In /kernel/drv/st.conf
tape-config-list =
    "HP      C1533A", "HP DDS2 4mm DAT", "HP-data2",
    "HP      HP35480A", "HP DDS-DC 4mm DAT", "HP-data1",
    "HP      HP35470A", "HP DDS 4mm DAT", "HP-data1",
    "HP      C1553A", "HP DDS2 4mm DATloader", "HP-data2";
HP-data1 = 1,0x34,0,0x8019,3,0x00,0x13,0x03,2;
HP-data2 = 1,0x34,0,0xd239,4,0x0,0x13,0x24,0x3,3;

# Note: block size is set to 0 or the driver will treat the device
#       as having a fixed block size. Net effect of NOT using a zero
#       block size is that large writes tend to get split into 1K
#       writes resulting in being unable to recover data.
#       See SunSolve bug #1200807
# Note: The space characters in the above strings are significant

and the switch settings are:

        1       2       3       4       5       6       7       8

        ON      ON      ON      ON      ON      OFF     OFF     OFF

boot -r

Compression control via device file name

This ability exists only on drives with firmware dated after Nov 1994. If your drive firmware is not new enough to support this then don't contact HP to obtain upgrade tapes. Firmware upgrades are at the discretion of drive distributors. You would be just as well to use the DC control utility supplied.

You need to set the config switches to:

        1       2       3       4       5       6       7       8

        ON      ON      OFF     OFF     ON      ON      OFF     OFF
Make the st_conf.c entries described in section 13. You should now be able to control compression via device file name:


b = Berkley mode
n = No rewind
l = Low density (compression disabled)
m = Medium Density (compression unchanged)
h = High Density   (compression unchanged)
c = Compression    (compression enabled)
If you can't open the device then it might well be due to the drive's firmware being too old. You will need to use the "old" config switches and rely on the DC control utility.

dump parameters

dump bds 64 15000  7000   /* 60m tape */
dump bds 64 15000 11000   /* 90m tape */
dump bds 64 15000 22000   /* 120m tape DDS2 format */
The block size is set to 64Kbytes for optimum SCSI performance. Capacity calculations are as follows:
15000 * 12 * 110000 = 1.98 Gbytes:

12 = inches per foot.
11000 = "notional" length of a 90m tape (in feet).
15000 = "notional" bit density (in bits/inch) of a DDS1 format tape. (note that since dump assumes 9 track wide tape, bits convert to bytes for capacity calculations).

With data compressing drives you might want to factor this into the equation by adjusting the "length" of the tape to adjust for compression ratio. eg. if you reckon you're getting 2X compression then set the tape length to 15000 * 2. Its fair to say that dump + data compression don't get along too well. If your compression ratio "dipps" then suddenly dump will run off the end of tape.

NB: All dump parameters above have been "kept below" 65536 since some versions of dump don't seem to handle "long" values.

Configuring DDS drives on IBM RS6000 systems

Configuration Switch Settings

Switches on drive underside should be set to either: <.br> 12345678=11011000 ( MRS off)
or 12345678=11011001 ( MRS on).


With the release of version 9 firmware for the HP35470/80A and the release of Version 3.2 or later of IBM's AIX operating system, the HP DDS drive now plug and play on the RS6000 without special firmware. Just plug in an HP DAT with version 9 firmware, and then use the IBM 'SMIT' program to configure your system. The HP DAT drives are compatible with the 'Other SCSI Devices' driver in SMIT.

In order to make the DDS tape dives operate with the IBM RS6000 family of workstations running old 3.1.X versions of the AIX operating system, HP provides 'special' firmware that emulated IBM's QIC drives. This allows the user to simply plug the HP35470/80A drive to the RS6000 workstation, and start backing up and restoring data, with no changes to the AIX operating systems files. This 'special' firmware is 'RS6K QIC Emulation Code', and must be downloaded into the drive prior to operation with the RS6000.

The drive will work with the 'tar', 'cpio', 'dd'. The drive is also boot capable, provided a boot tape is generated. For those customers who want to use the AIX 'backup' and 'restore' utilities, the drive's default condition must be 'fixed mode' and therefore Switch 5 needs to be set to 'OFF ' in this case.

Configuring DDS drives on DEC systems

Configuration Switch Settings

Switches on drive underside should be set to either: <.br> 12345678=11111110 ( MRS off), DEC3100, 5000 Ultrix/VMS
12345678=11111010 ( MRS off), DEC3100, 5000 Ultrix/VMS (better performance)
12345678=11011110 ( MRS on), DEC3100, 5000 Ultrix/VMS
12345678=11011010 ( MRS on), DEC3100, 5000 Ultrix/VMS (better performance)

The SCSI command set used on DEC workstations differ from that of SUN in one major area. This is the Space command. Where Sun complies to the requirements of SCSI-2 here, DEC chose to stay with a SCSI-1 implementation of this command. This slight difference is a major impact if a DEC user wants to boot from tape.

As a result, we provided the drives with this functionality. By setting Switch 8 to 0 or OFF, the drive automatically switches to the functionality required by DEC workstations. This will allow the user to plug and play on all DEC 3100 or 5000 Series Workstations running Ultrix or VMS. No other changes are required.

Additionally, in DEC latest release of VMS (5.5) new firmware is required in the HP DDS drive. Version 9 firmware, released in September of 1992, makes the drives fully compatible with VMS 5.5 or later operating systems. Also, in order to make the drive pass the DEC SCSI test during an 'Auto-boot' sequence, special code is required that reduces the number of bytes passed from the drive to the host from 43 to 40. This code is available from your technical representative.

Also, if top performance is a requirement, the drive can be configured to operate in the 'Performance' mode by setting switches 8 and 6 to 0 or OFF. This will increase the drives performance by reducing the time it takes to write filemarks, because all filemark commands will be treated as immediate commands. The drawback here is that if power fails, the host may not be able to figure out where data is, because a filemark that was supposedly on tape, has now been lost in the buffer. this is however the way the competitors drives operate all the time.

Configuring DDS drives on SGI systems

Configuration Switch Settings

Switches on drive underside should be set to either: <.br> 12345678=11101000 ( MRS off)

To make the HP35470/80A DDS drives compatible with Silicon Graphics workstations, the following modifications to the operating system are recommended;

In the file /usr/sysgen/master.d/tpsc, add the following paragraph after the Archive DAT entry;

{DATTAPE, TPDAT,7,6,"ARCHIVE","PYTHON",0,0,{0,0,0,0},
/*minimum delay to i/o is 4 minutes, because when a retry is
 *performed, the drive retries a number of times, and then
 *rewinds to BOT, repositions, and tries again. */

(New paragraph starts here)

{DATTAPE, TPDAT,2,8,"HP","HP354xxA",0,0,{0,0,0,0},
/*minimum delay to i/o is 4 minutes, because when a retry is
 *performed, the drive retries a number of times, and then
 *rewinds to BOT, repositions, and tries again. */
Recompile your kernel and then you are ready to start backing up files to the HP drive.

To read SGI written tar tapes on an HP system: dd if=/dev/rmt/0m ibs=20k obs=512 bs=512k | tar xvf -

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