Date: Fri, 27 Feb 2015 23:47:56 -0700 From: "Kenneth D. Merry" <ken@FreeBSD.ORG> To: Dan Langille <dan@langille.org> Cc: current@freebsd.org, scsi@freebsd.org Subject: Re: sa(4) driver changes available for test Message-ID: <20150228064756.GA40281@mithlond.kdm.org> In-Reply-To: <5568AE5F-193C-47A8-A24B-FB2C36E37BC9@langille.org> References: <20150214003232.GA63990@mithlond.kdm.org> <7CA52DF3-E073-4F50-BE4E-01C51CCDF2C7@langille.org> <20150217183645.GA30947@mithlond.kdm.org> <5568AE5F-193C-47A8-A24B-FB2C36E37BC9@langille.org>
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On Fri, Feb 27, 2015 at 17:56:42 -0500, Dan Langille wrote: > > > On Feb 17, 2015, at 1:36 PM, Kenneth D. Merry <ken@freebsd.org> wrote: > > > > On Sat, Feb 14, 2015 at 18:22:43 -0500, Dan Langille wrote: > >> > >>> On Feb 13, 2015, at 7:32 PM, Kenneth D. Merry <ken@freebsd.org> wrote: > >>> > >>> > >>> I have a fairly large set of changes to the sa(4) driver and mt(1) driver > >>> that I'm planning to commit in the near future. > >>> > >>> A description of the changes is here and below in this message. > >>> > >>> If you have tape hardware and the inclination, I'd appreciate testing and > >>> feedback. > >> > >> I have a DLT 8000 and an SDLT 220. > >> > >> I don't have anything running current, but I have a spare machine which I could use for testing. > >> > >> Do you see any value is tests with that hardware? I'd be testing it via Bacula. > >> > >> disclosure: I'm the sysutils/bacula-* maintainer and a Bacula committer. > >> > > > > Actually, yes. Bacula is a bit tricky to configure, so your trying it out > > would be helpful if you have the time. > > I have been unable to test yet. I've encountered time and hardware issues. I know how that goes! (On both counts.) > I may be able to try tomorrow. So I have tested building it and it does build at least. If you're able to figure out some of the answers below, that would be great! > > > > In looking at the manuals for both the SDLT 220 and the DLT 8000, they both > > claim to support long position information for the SCSI READ POSITION > > command. > > > > You can see what I'm talking about by doing: > > > > mt eod > > mt status > > > > On my DDS-4 tape drive, this shows: > > > > # mt -f /dev/nsa3 status > > Drive: sa3: <SEAGATE DAT 06240-XXX 8071> Serial Number: HJ00YWY > > --------------------------------- > > Mode Density Blocksize bpi Compression > > Current: 0x26:DDS-4 1024 bytes 97000 enabled (DCLZ) > > --------------------------------- > > Current Driver State: at rest. > > --------------------------------- > > Partition: 0 Calc File Number: -1 Calc Record Number: -1 > > Residual: 0 Reported File Number: -1 Reported Record Number: -1 > > Flags: None > > > > But on an LTO-5, which will give long position information, I get: > > > > [root@doc ~]# mt status > > Drive: sa0: <IBM ULTRIUM-HH5 E4J1> > > --------------------------------- > > Mode Density Blocksize bpi Compression > > Current: 0x58:LTO-5 variable 384607 enabled (0x1) > > --------------------------------- > > Current Driver State: at rest. > > --------------------------------- > > Partition: 0 Calc File Number: 2 Calc Record Number: -1 > > Residual: 0 Reported File Number: 2 Reported Record Number: 32373 > > Flags: None > > > > That, in combination with the changes I made to the position information > > code in the driver, mean that even the old MTIOCGET ioctl should return an > > accurate file number at end of data. e.g., on the LTO-5: > > > > [root@doc ~]# mt ostatus > > Mode Density Blocksize bpi Compression > > Current: 0x58:LTO-5 variable 384607 0x1 > > ---------available modes--------- > > 0: 0x58:LTO-5 variable 384607 0x1 > > 1: 0x58:LTO-5 variable 384607 0x1 > > 2: 0x58:LTO-5 variable 384607 0x1 > > 3: 0x58:LTO-5 variable 384607 0x1 > > --------------------------------- > > Current Driver State: at rest. > > --------------------------------- > > File Number: 2 Record Number: -1 Residual Count -1 > > > > So the thing to try, in addition to just making sure that Bacula continues > > to work properly, is to try setting this for the tape drive in > > bacula-sd.conf: > > > > Hardware End of Medium = yes > > > > It looks like the Bacula tape program (btape) has a test mode, and it would > > be good to run through the tests on one of the tape drives and see whether > > they work, and whether the results are different before and after the > > changes. I'm not sure how to enable the test mode. > > > >> I'll let the other Bacula devs know about this. They deal with the hardware. I work on PostgreSQL. > >> > > > > Thanks! If there are additional features they would like out of the tape > > driver, I'm happy to talk about it. (Or help if they'd like to use the new > > status reporting ioctl, MTIOCEXTGET or any of the other new ioctls.) > > > > Ken > > -- > > Kenneth Merry > > ken@FreeBSD.ORG > > ? > Dan Langille > http://langille.org/ > > > > > Ken -- Kenneth Merry ken@FreeBSD.ORG
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