Date: Mon, 12 Apr 1999 09:46:04 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: "Kenneth D. Merry" <ken@plutotech.com> Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: odd performance 'bug' & other questions Message-ID: <14097.62839.525472.52389@grasshopper.cs.duke.edu> In-Reply-To: <199904120049.SAA01682@panzer.plutotech.com> References: <14097.8430.806061.277769@grasshopper.cs.duke.edu> <199904120049.SAA01682@panzer.plutotech.com>
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Kenneth D. Merry writes: > > There are a couple of things going on here that may affect the performance > numbers you're seeing: > > - There was a performance problem in getnewbuf() that was supposedly fixed > on April 6th. I haven't tested -current since then, so I don't know for > sure whether the problem is really fixed. I know about this, so I am using dd rather than Bonnie / iozone in order to factor this out. It sure would be nice if Matt's fix surfaced though ;-) > - The Medalist Pro drives are known to be rather crappy. That's why we've > got the number of tags set to 2 in the quirk entry for those drives. Crap, crap, crap. We just bought 84 of these; I wish I could have talked my boss into the barracudas.. > > Using camcontrol to look at the defects list on some of these drives, > > I see that its HUGE. I've seen one disk with over 1100 entries in the > > primary defects list. Should I be alarmed at the size of the defects > > list? Should I complain to my vendor, or is this typical? > > Well, it varies. I've got four disks on a heavily used server: > > <SEAGATE ST19171N 0023> at scbus0 target 0 lun 0 (pass0,da0) > <SEAGATE ST19171N 0023> at scbus0 target 1 lun 0 (pass1,da1) > <IBM DGHS18Z 03E0> at scbus0 target 3 lun 0 (pass2,da2) > <SEAGATE ST19171N 0024> at scbus1 target 0 lun 0 (pass3,da3) > > Here are the defect numbers, in order: > > Got 464 defects: > Got 144 defects: > Got 1145 defects: > Got 579 defects: > > I've also got the following disk on my home machine: > > <IBM DGVS09U 03B0> at scbus1 target 1 lun 0 (pass1,da1) > > And it has 660 defects in the permanant list, none in the grown defect > list. It is a 9G drive, and still gives pretty good performance. > (14-16MB/sec) So your numbers are a bit high for a 9G drive, but I'm not > sure whether that would be considered excessive. Of course the drives I've > got above are higher-end Seagate and IBM disks, not low-end models. And > you'd expect the number of defects to be somewhat proportional to the > capacity of the drive. Your numbers are closer to the 18G IBM disk above. OK.. so they're a bit bad, but not necessarily unusual. I haven't paid much attention to defect lists since a 1GB disk was considered large, so I guess I was just a bit surprised to see the size. Thanks for the feedback. <..> > > Also, the ncr controller fails to give me a defects list, I assume > > this is a bug in the driver? (I'm running -current, dated this Thurs). > > camcontrol complains: error reading defect list: Input/output error, > > and I see this on console: > > > > (pass3:ncr0:0:0:0): extraneous data discarded. > > (pass3:ncr0:0:0:0): COMMAND FAILED (9 0) @0xc39a3600. > > It could be a driver bug, not sure. What arguments were you using with > camcontrol? camcontrol defects -n da -u 3 -f phys -P When the unit is one of the drives attached to the on-board adaptec controller, it works as expected. However, if the unit is a drive attached to the ncr crontoller, the command fails as mentioned above. The drives are identical, so that's why I'm assuming there's an ncr bug. Cheers, Drew ------------------------------------------------------------------------------ Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin Duke University Email: gallatin@cs.duke.edu Department of Computer Science Phone: (919) 660-6590 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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