Date: Wed, 21 Aug 2002 22:18:24 -0400 From: "Mike Stackhouse" <mike@samsa.com> To: <questions@freebsd.org>, "Derek" <derek@durham.net>, "Brian T. Schellenberger" <bts@babbleon.org> Subject: Re: Promise ATA RAID FastTrak100 TX2 Pro for Freebsd 4.5 Message-ID: <200208212218.AA73335054@samsa.com>
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Thanks - where would we disable write cache? Mike ---------- Original Message ---------------------------------- From: "Brian T. Schellenberger" <bts@babbleon.org> Date: Wed, 21 Aug 2002 21:45:52 -0400 >On Wednesday 21 August 2002 09:23 pm, Mike Stackhouse wrote: >| Thanks - we'll try without softupdates. > >Softupdates should increase both performance and reliability, at the >cost of sometimes making you "seem" to have less disk space than you >actually have when the updates are behind the requests. > >(This problem is apparently fixed in -CURRENT, though.) > >So there's no reason not to try it and see what happens but I'd be >surprised if it *helped* performance to turn off softupdates. Another >thing that of course that has an huge impact on performance is write >caching; disabling it is slower but safer; enabling it is faster but >more dangerous. > >Personally I take advantage of the increased performance that >softupdates gets me to disable the write caching. This is much safer >than without softupdates and with write caching and only slightly >slower. > >I personally strong recommend *against* enabling both write caching and >softupdates at the same time; it should be very fast but in my >experience it makes it very, very easy to lose state on power-down. > >| Interesting comment on no support for hot swap. > >Support for hot swap in ATA was added during the 4.5-STABLE period and >is in 4.6-RELEASE. It is not present in 4.5-RELEASE. Unfortunately, >the "new" ATA code that added this support also broke some ATA stuff, >especially w/r/t CD-ROMs, so a test configuation might be advisable >first to make sure that the cure isn't worse than the disease. > >| Our whole intention >| for raid-1 is to prevent system downtime in case of drive failure. >| From your comment, doesn't sound like FreeBSD supports this? Would >| our only alternative be software raid? >| >| Thanks in advance! >| ---------- Original Message ---------------------------------- >| From: "Derek" <derek@durham.net> >| Date: Wed, 21 Aug 2002 16:22:12 -0400 >| >| >> Is there something we should do to optimize our configuration? >| > >| >We have installed the very same product on one of our FreeBSD >| >boxen, it was 4.4-STABLE when we ran the install program, and >| >every thing went smooth. I believe this was before softupdates >| >was enabled by default. Perhaps when you are creating your mount >| >points you could try disabling softupdates and see if that makes >| >a difference. >| > >| >As a side note (that you might want to know), I don't believe >| >that the driver in FreeBSD supports hot swap. At least any time >| >we've had a drive fail, we get a kernel panic, and it's rebuild >| >mirror from the card's BIOS. >| > >| >Regards, >| >Derek >| >| To Unsubscribe: send mail to majordomo@FreeBSD.org >| with "unsubscribe freebsd-questions" in the body of the message > >-- >Brian, the man from Babble-On . . . . bts@babbleon.org (personal) > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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