Driver-Taper protocol: Difference between revisions
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* If something goes wrong with the tape, taper can ask to continue on a new tape SPLIT-NEEDNEXT (for splited dump only) or it can abort that dump with PARTIAL or FAILED reply | * If something goes wrong with the tape, taper can ask to continue on a new tape SPLIT-NEEDNEXT (for splited dump only) or it can abort that dump with PARTIAL or FAILED reply | ||
* After any dump that finished in PARTIAL or FAILED with a TAPE-ERROR, the driver must send a NEW-TAPE before issuing another *-WRITE command. | |||
==Other commands== | ==Other commands== |
Revision as of 17:54, 16 October 2006
Communication method
driver talks via two pipes connected to taper's stdin and stdout. The commands and responses are plain text.
Command sequence during backup operation
- driver initialises taper with: START-TAPER <datestamp> to which taper replies with: TAPE-OK or, for fatal errors, with: TAPE-ERROR [<message>]
- driver will ask the taper to start a new tape with the NEW-TAPE command.
- driver can ask taper to copy a file from the holding disk to tape: FILE-WRITE <handle> <filename> <host> <disk> <level> or directly from a dumper: PORT-WRITE <handle> <host> <disk> <level> or exit at the end of the run: QUIT
- taper responds to the PORT-WRITE command with: PORT <port> which driver should then hand on to dumper in a PORT-DUMP command.
- If the copy to tape finishes correctly taper replies with: DONE <handle> [<message>]
- If something goes wrong with the tape, taper can ask to continue on a new tape SPLIT-NEEDNEXT (for splited dump only) or it can abort that dump with PARTIAL or FAILED reply
- After any dump that finished in PARTIAL or FAILED with a TAPE-ERROR, the driver must send a NEW-TAPE before issuing another *-WRITE command.
Other commands
- If driver says something that taper doesn't recognise it responds with: BAD-COMMAND <message>
- taper responds to the QUIT command with: QUITING
Protocol data
data | description |
---|---|
<datestamp> | Date as "yymmdd" |
<handle> | Request ID |
<filename> | Name of file on the holding disk where backup will be written to |
<port> | Taper port to send the backup data to |
<host> | Hostname of the client |
<disk> | Disk on the client being backed up |
<level> | Dump level being used for backup |
<message> | Error or Status message |
Protocol command reference
Taper command reply
Reply | Description |
---|---|
TAPE-OK | taper is setup correctly |
TAPE-ERROR | Error in setup of the driver |
PORT | Reply sent in response to PORT-WRITE command |
DONE | Full dump is on the media |
PARTIAL | Dump was partially written to the media. |
FAILED | Nothing was written to the media |
SPLIT-CONTINUE | A complete part is written to tape |
SPLIT-NEEDNEXT | Ask driver if it should continue on a new tape |
NEW-TAPE | Will continue on a new found tape |
NO-NEW-TAPE | Will not continue on a new tape |
DONE/PARTIAL and FAILED reply also contains an INPUT-* an TAPE-* message to denote any error:
Reply | Description |
---|---|
INPUT-GOOD | There was no error with the input. |
INPUT-ERROR | There was error with the input. |
Reply | Description |
---|---|
TAPE-GOOD | This tape can be use to write another dump. |
TAPE-ERROR | Nothing more can fit on that tape. |
A result for a successful dump should be: DONE INPUT-GOOD TAPE-GOOD
Driver/Taper Requests/Replies
Driver request | Taper reply | Description | |
---|---|---|---|
initail setup | |||
START-TAPER | ---> | ||
<--- | TAPE-OK | normal taper setup (a tape is available, nothing is written on it) | |
<--- | TAPE-ERROR | failed taper setup (no tape are available or something else is broken) | |
ask for new tape | |||
NEW-TAPE | ---> | driver tell the taper to use a new tape | |
<--- | GOT-NEW-TAPE | taper found one | |
<--- | NO-NEW-TAPE | no tape are available | |
file-write setup | |||
FILE-WRITE | ---> | ||
Will get one part-result for each part written and one global result | |||
port-write setup | |||
PORT-WRITE | ---> | ||
<--- | PORT | ||
WIll continue with one part-result for each part written and one global result | |||
global-result | |||
<--- | DONE INPUT-GOOD TAPE-GOOD | normal protocol for a success | |
<--- | PARTIAL INPUT-* TAPE-* | protocol for error in data phase (something written to tape) | |
<--- | FAILED INPUT-* TAPE-* | protocol for error in setup (before something is written to tape) | |
part-result | |||
<--- | SPLIT-CONTINUE | successfully part written to tape | |
<--- | SPLIT-NEEDNEXT | failed PART (only for tape-error) (driver will send a NEW-TAPE or NO-NEW-TAPE command) | |
no new tape | |||
NO-NEW-TAPE | ---> | driver doesn't want the taper to use a new tape (continue with global-result) |