Date: Fri, 14 Jul 1995 04:00:04 -0700 From: gordon@sneaky.lonestar.org To: freebsd-bugs Subject: kern/614: SCSI tape timeout for forward space file is too short Message-ID: <199507141100.EAA03785@freefall.cdrom.com> In-Reply-To: Your message of Thu, 13 Jul 95 13:42 CDT <m0sWTDX-0001hDC@hammy.lonestar.org>
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>Number: 614 >Category: kern >Synopsis: SCSI tape timeout for forward space file is too short >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs (FreeBSD bugs mailing list) >State: open >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Fri Jul 14 04:00:01 1995 >Originator: Gordon Burditt >Organization: what organization? >Release: FreeBSD 2.0-BUILT-19950603 i386 >Environment: FreeBSD 2.0.5 AHA1542B SCSI controller (aha0:1:0): "WANGTEK 51000 SCSI REV7 3J" type 1 removable SCSI 1 st0(aha0:1:0): Sequential-Access density code 0xf, 512-byte blocks, write-enabled >Description: Finally multiple-files-per-tape is working on this tape drive, so I started putting 4 dumps per tape. When I went to recover something from the last dump (restore ibsf 20 4 /dev/rst0), the "forward space file" operation timed out, along with driver complaints about "mailbox not free". Things went downhill rapidly as sd0 contains important parts of the system, and it was getting timeout errors also. Eventually it rebooted itself. 10 minutes is not enough time for a forward-space-file, or especially multiple forward-space-files. Writing or reading a full tape (Doesn't seem to vary a lot whether I use 525M, 250M, or 120M tapes, either) takes somewhere in the vicinity of 45 minutes to just under an hour. I suspect forward-space-file is done at the same speed as reading the tape. Separate timeouts for "forward space file" and "forward space record" might be appropriate. >How-To-Repeat: Create a 6525 tape with multiple dumps on it. Fill up most of the tape, so the beginning of the last dump is well into the tape. restore ibsf 20 4 /dev/rst0 (where 4 represents the number of the last dump). With 6525 tapes and my tape drive, a blocking factor of 20 is required, according to complaints from the kernel if I forget to use it. >Fix: Apply the following patch, and rebuild the kernel. Index: /usr/src/sys/scsi/st.c *** 1.1 1995/07/11 20:56:49 --- st.c 1995/07/11 20:57:37 *************** *** 1681,1687 **** 0, 0, 0, /* no retries please , just fail */ ! 600000, /* 10 mins enough? */ NULL, flags)); } --- 1681,1687 ---- 0, 0, 0, /* no retries please , just fail */ ! 3600000, /* 10 mins enough? No, but an hour might be */ NULL, flags)); } >Audit-Trail: >Unformatted:
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