Date: Fri, 27 Feb 2015 17:56:42 -0500 From: Dan Langille <dan@langille.org> To: "Kenneth D. Merry" <ken@freebsd.org> Cc: current@freebsd.org, scsi@freebsd.org Subject: Re: sa(4) driver changes available for test Message-ID: <5568AE5F-193C-47A8-A24B-FB2C36E37BC9@langille.org> In-Reply-To: <20150217183645.GA30947@mithlond.kdm.org> References: <20150214003232.GA63990@mithlond.kdm.org> <7CA52DF3-E073-4F50-BE4E-01C51CCDF2C7@langille.org> <20150217183645.GA30947@mithlond.kdm.org>
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> On Feb 17, 2015, at 1:36 PM, Kenneth D. Merry <ken@freebsd.org> wrote: >=20 > On Sat, Feb 14, 2015 at 18:22:43 -0500, Dan Langille wrote: >>=20 >>> On Feb 13, 2015, at 7:32 PM, Kenneth D. Merry <ken@freebsd.org> = wrote: >>>=20 >>>=20 >>> 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. >>>=20 >>> A description of the changes is here and below in this message. >>>=20 >>> If you have tape hardware and the inclination, I'd appreciate = testing and >>> feedback. >>=20 >> I have a DLT 8000 and an SDLT 220. >>=20 >> I don't have anything running current, but I have a spare machine = which I could use for testing. >>=20 >> Do you see any value is tests with that hardware? I'd be testing it = via Bacula. >>=20 >> disclosure: I'm the sysutils/bacula-* maintainer and a Bacula = committer. >>=20 >=20 > 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 may be able to try tomorrow. >=20 > 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. >=20 > You can see what I'm talking about by doing: >=20 > mt eod > mt status >=20 > On my DDS-4 tape drive, this shows: >=20 > # 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 >=20 > But on an LTO-5, which will give long position information, I get: >=20 > [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 >=20 > 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: >=20 > [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 >=20 > 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: >=20 > Hardware End of Medium =3D yes >=20 > 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. >=20 >> I'll let the other Bacula devs know about this. They deal with the = hardware. I work on PostgreSQL. >>=20 >=20 > 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.) >=20 > Ken > --=20 > Kenneth Merry > ken@FreeBSD.ORG =E2=80=94=20 Dan Langille http://langille.org/
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