Date: Wed, 21 Aug 2002 22:42:01 -0400 From: "Brian T. Schellenberger" <bts@babbleon.org> To: <mike@samsa.com>, <questions@freebsd.org>, "Derek" <derek@durham.net> Subject: Re: Promise ATA RAID FastTrak100 TX2 Pro for Freebsd 4.5 Message-ID: <200208212242.01475.bts@babbleon.org> In-Reply-To: <200208212218.AA73335054@samsa.com> References: <200208212218.AA73335054@samsa.com>
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Add the following to /boot/loader.conf hw.ata.wc=0 This will slow down your i/o considerably. I'm not sure that's what you want, though; I thought you were trying to optimize your performance, not degrade it. It will make your data a lot safer. One of those tradeoffs . . . On Wednesday 21 August 2002 10:18 pm, Mike Stackhouse wrote: | 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) -- 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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