lto-scripts/README.MD

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2022-03-24 11:16:05 +01:00
# LTO Backup Scripts
Scripts to help me perform my backups to Ultrium LTO tapes.
## Movies Library
* `mkbak_media.sh`: Incremental subdirectory backup. Take each directory in my cwd, tar it, and append it to tape, one tape entry per directory. Create / extend a CSV index denoting when and to what tape ID the backup was made. Do not backup directories that were already backed up to other media (using the index). Note: Changes in directories will not be detected. The directory name is the only clue.
# LTO Notes
## General stuff
* dev/nst does not auto-rewind, dev/st does
* use mt-st seek / tell to position the tape at block indexes
* Remaining capacity: https://serverfault.com/questions/853302/determine-remaining-capacity-of-lto-tape
* `sg_logs -a $DEV | sed -n 's/\s*Main partition remaining capacity (in MiB):\s*\(.*\)/\1/p'`
* Disable compression: `mt-st -f /dev/nst0 compression 0`
* Make seek/tell work: `mt-st -f /dev/nst0 stsetoptions scsi2logical`
## Improve start/stop
If you have a slow source / destination, consider using mbuffer with a size of a couple of Gigs. But that might also break speed matching, causing start / stop rather than going slower... idk.
## Backups
### Encrypted tar using GPG
`tar cvO --exclude dir/excludeme dir/ | gpg --encrypt --sign --default-key KEY-ID -r KEY-ID -z 0 dd of=/dev/nst0 bs=512k`
To decrypt, simply use `gpg --decrypt /dev/nst0`
# LTFS on LTO-6
My drives are a little weird, to get it to work I need to edit LTFS sources.
`ltfs-2.4.3.1-10461/src/tape_drivers/linux/sg/sg_tape.c`: Type is incorrectly auto detected, we need to always `/* Use LogPage 0x31 */`
See this patch for inspiration
```
diff --git a/src/tape_drivers/linux/sg/sg_tape.c b/src/tape_drivers/linux/sg/sg_tape.c
index f583079..1169e44 100644
--- a/src/tape_drivers/linux/sg/sg_tape.c
+++ b/src/tape_drivers/linux/sg/sg_tape.c
@@ -513,6 +513,12 @@ static int _raw_open(struct sg_data *priv)
return -EDEV_DEVICE_UNSUPPORTABLE; /* Unsupported device */
}
+ /* Special care about Quantum model B */
+ if (priv->vendor == VENDOR_QUANTUM) {
+ if (id_data.product_id[7] == ' ')
+ priv->vendor = VENDOR_QUANTUM_B;
+ }
+
if (priv->drive_serial[0]) {
/* if serial number is already set, compare it */
if (strcmp(priv->drive_serial, id_data.unit_serial)) {
@@ -2969,7 +2975,8 @@ int sg_remaining_capacity(void *device, struct tc_remaining_cap *cap)
memset(buffer, 0, LOGSENSEPAGE);
if ((IS_LTO(priv->drive_type) && (DRIVE_GEN(priv->drive_type) == 0x05)) ||
- (priv->vendor == VENDOR_HP && IS_LTO(priv->drive_type) && (DRIVE_GEN(priv->drive_type) == 0x06))) {
+ (priv->vendor == VENDOR_HP && IS_LTO(priv->drive_type) && (DRIVE_GEN(priv->drive_type) == 0x06)) ||
+ (priv->vendor == VENDOR_QUANTUM_B && IS_LTO(priv->drive_type))) {
/* Use LogPage 0x31 */
ret = sg_logsense(device, (uint8_t)LOG_TAPECAPACITY, (uint8_t)0, (void *)buffer, LOGSENSEPAGE);
diff --git a/src/tape_drivers/tape_drivers.h b/src/tape_drivers/tape_drivers.h
index a9d7bf5..6e11771 100644
--- a/src/tape_drivers/tape_drivers.h
+++ b/src/tape_drivers/tape_drivers.h
@@ -178,6 +178,7 @@ enum {
VENDOR_IBM,
VENDOR_HP,
VENDOR_QUANTUM,
+ VENDOR_QUANTUM_B,
};
enum {
```