SAN Client backups failing intermittently with STATUS 174
|Article:TECH147561|||||Created: 2011-01-06|||||Updated: 2012-08-18|||||Article URL http://www.symantec.com/docs/TECH147561|
In certain circumstances SAN Client backups can fail with STATUS 174, if the client have utilities or programs which use a Test Unit Ready (TUR) commands whilst data is being sent via the SAN/Fibre. This can cause sequence errors in the Fibre Transport (FT) communication, which will cause the backup to fail because of unexpected data being received by the media server.
Critical bptm(pid=xxxxx) data buffers out of sequence, expected number 1842595, received 1842598 <<<---Received number is higher
Critical bptm(pid=xxxxx) data buffers out of sequence, expected number 17, received 20
11:44:35.144  <32> write_data: data buffers out of sequence, expected number 17, received 20
11:44:35.144  <2> write_backup: write_data() returned, exit_status = 174, CINDEX = 0, TWIN_INDEX = 0, backup_status = -8
NBFTSRVR (OID:199) log
06/22/09 11:44:34.297 [Debug] NB 51216 FATServer 199 PID:7667 TID:4124814240 File ID:199 [No context] 1 [ProcessReadWrite] BUFFER sequence error, cmd = 0x0x3b, pipe = 0x0x1, ftseq = 0x0x10, rseq = 0x0x13, state = 0x0x1
06/22/09 11:44:34.297 [Debug] NB 51216 FATServer 199 PID:7667 TID:4124814240 File ID:199 [No context] 1 [ProcessReadWrite] WRITE BUFFER sequence error 16 19
NetBackup 6.5.6, SAN Client backups
The TUR commands can be sent when clients have multi-pathing or other monitoring software
The official resolution currently, is to determine what is causing the TUR commands and to prevent then from occurring.
Symantec Engineering (Etrack:1736627) have adjusted the NetBackup code from NetBackup 6.5.6 to include a new touch file ( /usr/openv/var/FTCLIENT_VALIDATE_VIA_CHECK_CONDITION ). This touch file needs to be created on the client(s) experiencing the STATUS 174 failures. After the touch file is created (NetBackup FT client service requires a restart), additional Client Data Block (CDB) information is supplied which counteracts the problems when the additional TUR data is sent. Unfortunately, there will be a slight reduction in performance as the CDBs are sent twice.
Periodic data buffer sequence failures backing up Linux clients
Article URL http://www.symantec.com/docs/TECH147561