Hello
Recently I exchange the LTO2 tape drives to brand new LTO4 with new LTO4 media. And now almost half of new tapes are being frozen by NBU. In BPTM logs I do see such entries:
01:01:09.058 [3473466] <2> send_MDS_msg: DEVICE_STATUS 1 438127 taqa1d01 L00029 4000900 Drive5 2000056 TAPE_ALERT 872579072 0
01:01:09.078 [3473466] <2> log_media_error: successfully wrote to error file - 07/01/10 01:01:09 L00029 2 TAPE_ALERT Drive5 0x34028000 0x00000000
01:01:09.079 [3473466] <2> db_error_add_to_file: dberrorq.c:midnite = 1277960400
01:01:09.088 [3473466] <8> process_tapealert: TapeAlert Code: 0x03, Type: Warning, Flag: HARD ERROR, from drive Drive5 (index 2), Media Id L00029
01:01:09.088 [3473466] <2> db_error_add_to_file: dberrorq.c:midnite = 1277960400
01:01:09.099 [3473466] <16> process_tapealert: TapeAlert Code: 0x04, Type: Critical, Flag: MEDIA, from drive Drive5 (index 2), Media Id L00029
01:01:09.099 [3473466] <2> db_error_add_to_file: dberrorq.c:midnite = 1277960400
01:01:09.109 [3473466] <16> process_tapealert: TapeAlert Code: 0x06, Type: Critical, Flag: WRITE FAILURE, from drive Drive5 (index 2), Media Id L00029
01:01:09.109 [3473466] <2> db_error_add_to_file: dberrorq.c:midnite = 1277960400
01:01:09.130 [3473466] <8> process_tapealert: TapeAlert Code: 0x0f, Type: Warning, Flag: MIC FAILURE, from drive Drive5 (index 2), Media Id L00029
01:01:09.130 [3473466] <2> db_error_add_to_file: dberrorq.c:midnite = 1277960400
01:01:09.142 [3473466] <8> process_tapealert: TapeAlert Code: 0x11, Type: Warning, Flag: READ ONLY, from drive Drive5 (index 2), Media Id L00029
01:01:09.175 [3473466] <2> vnet_vnetd_service_socket: vnet_vnetd.c.2043: VN_REQUEST_SERVICE_SOCKET: 6 0x00000006

L00029 1 6 07/01/2010 00:14 07/01/2010 00:14 hcart 154415443 0
MPX 07/11/2010 00:14 N/A FROZEN

NBU 6.5.1 is running on AIX 5.3. Tapes are
Manufacturer................IBM
Machine Type and Model......ULTRIUM-TD4
Serial Number...............xxxxxxxx
Device Specific.(FW)........94D7
installed in L700.

What do you think ? Issues are related to:
a) tapes itself
b) tape drives
c) nbu
any clues are welcome.
Of course some backup jobs to some tapes are doing good. The above errors was seen for all drives, for various media.
Do you think it would be good idea to clean brand new drives, even where there is no tape alert about cleaning needed?
I checked the tape alert PDF and here is the desc for these errors:
3 Hard Error W
The operation has stopped because an error has occurred while reading or writing data which the drive cannot correct.
The drive had a hard read or write error
4 Media C
Your data is at risk:
1. Copy any data you require from this tape.
2. Do not use this tape again.
3. Restart the operation with a different tape.
Media can no longer be written/read, or performance is severely degraded
6 Write Failure C
The tape is from a faulty batch or the tape drive is faulty:
1. Use a good tape to test the drive.
2. If the problem persists, call the tape drive supplier helpline.
The drive can no longer write data to the tape
15 Memory Chip in Cartridge Failure W
The memory in the tape cartridge has failed, which reduces performance. Do not use the cartridge for further backup operations.
Memory chip failed in cartridge
17 Read Only Format W
You have loaded a cartridge of a type that is read-only in this drive.
The cartridge will appear as write-protected
Media loaded that is read-only format

All points to bad media - imho - but so many bad medias? and brand new!!