Date: Mon, 20 Feb 2017 21:04:11 +0100 From: Dirk-Willem van Gulik <dirkx@webweaving.org> To: freebsd-hackers@freebsd.org Subject: sa and mpt in FreeBSD 11.0-RELEASE-p2 Message-ID: <C2E846C2-D96B-4429-8DC9-5612EF529F3E@webweaving.org>
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A machine, recently upgraded from 8.4 to FreeBSD 11.0-RELEASE-p2 seems = to have lost pretty much any and all performance on mpt(4) with its = attached tape drives Read performance is around 50Mbyte/second - and write a paltry = 100-200kbyte/second (and occasionally hitting 800kbyte/second) (from/to = memory disk&/dev/null; no risk of shoe shining, compression off). SCSI bus looks happy; with no kernel messages. Output of the DLT script = below. Normal LTO drives in a tape robot, G9 server; pretty much all SAS = *except* for a U320 to tape drive with the performance issue. Active = terminator. Does this ring a bell with anyone? Was anything changed in either the sa = or mpt driver since 8.x ?=20 One odd thing is that a 'dd(1)' -without- a block size (compression is = off, data is a prepared urandom file on md disk) writes much faster -- = while on 8.x one -had- to use a sane blockwise to get the 'normal' speed = of around 120Mbyte/second. Could it be that one needs to fiddle with = MAXPHYS (which AFAIK is a readonly sysctl). Dw. DLT / http://www.freebsddiary.org/tape-testing.php READING Corrected errors with substantial delay: 0 Corrected errors with possible delay : 0 Total errors : 0 Total errors corrected : 0 Total times correction algorithm used : 0 Total bytes processed : 8590352388 Total corrected errors / GB : 0 Total uncorrected errors : 0 Read compression ratio : 101% On tape Mbytes read : 2 On tape kbytes read residual : 329320 WRITING Corrected errors with substantial delay: 154 Corrected errors with possible delay : 0 Total errors : 0 Total errors corrected : 0 Total times correction algorithm used : 168 Total bytes processed : 4909148037124 Total corrected errors / GB : 0 Total uncorrected errors : 0 Write compression ratio : 99% Host requested Mbytes written : 1442 Host requested kbytes written residual : 115996 On tape Mbytes written : 1443 On tape kbytes written residual : 0 camcontrol devlist <QUANTUM ULTRIUM 4 W52T> at scbus3 target 5 lun 0 (sa0,pass0) <QUANTUM UHDL 0091> at scbus3 target 5 lun 1 (ch0,pass1) <HP RAID 0 OK> at scbus4 target 0 lun 0 (pass2,da0) <HP RAID 1(1+0) OK> at scbus6 target 0 lun 0 (pass3,da1) <HP RAID 0 OK> at scbus6 target 1 lun 0 (pass4,da2) <QUANTUM ULTRIUM 4 W52T> at scbus7 target 5 lun 0 (sa1,pass5) <QUANTUM UHDL 0091> at scbus7 target 5 lun 1 (ch1,pass6) mt rblim /dev/nsa0: min blocksize 1 byte max blocksize 16777215 bytes granularity 1 byte mt status, ostatus and errstatus Mode Density Blocksize bpi Compression Current: 0x46:LTO-4 variable 323215 disabled ---------available modes--------- 0: 0x46:LTO-4 variable 323215 0x1 1: 0x46:LTO-4 variable 323215 0x1 2: 0x46:LTO-4 variable 323215 0x1 3: 0x46:LTO-4 variable 323215 0x1 --------------------------------- Current Driver State: at rest. --------------------------------- File Number: 0 Record Number: 0 Residual Count 0 Drive: sa0: <QUANTUM ULTRIUM 4 W52T> Serial Number: HU1027B53Y --------------------------------- Mode Density Blocksize bpi Compression Current: 0x46:LTO-4 variable 323215 disabled --------------------------------- Current Driver State: at rest. --------------------------------- Partition: 0 Calc File Number: 0 Calc Record Number: 0 Residual: 0 Reported File Number: 0 Reported Record Number: 0 Flags: BOP Last I/O Residual: 0 Last I/O Command: 0A 00 02 00 00 00 00 00 00 00 00 00 00 00 00 00 Last I/O Sense: 70 00 0B 00 00 00 00 10 00 00 00 00 47 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Last Control Residual: 0 Last Control Command: 34 06 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Last Control Sense: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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