Messages in this thread | | | Date | Thu, 6 Oct 2005 23:47:18 -0700 (PDT) | From | Dan C Marinescu <> | Subject | Re: quick (software versus hardware raid) question (cpu) |
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it seams to me tha SCSI_SATA_SIL works with Sil 3114!
// happy now :-)
daniel
--- Dan C Marinescu <dan_c_marinescu@yahoo.com> wrote:
> hi there, > > i have a mission critical system with an unsuported > raid controller (4 sata channels, sil 3114). so, i > set > up a software raid... now, the problem is at pick > hours, when nics hardware interrupts compete with > the > software raid kernel thingie... i know you avoid > spawning threads but regarless the scheduller's > preeptivenes, the two kernel tasks are > scheduller-wise > competing and this is killing my server (slowing it > down, cpu is at 100% user and 40-60% kernel). > another > issue is that not being able to "see" the "bios" > partition (controller is totally unsuported) i > cannot > boot (unless i go like raid 1 on /boot). so what > about > performance? what about scalability? if case of 1 > array (hardware raid) versus n distinct sata > connectors, you big o notation goes like O(n) > instead > of O(1), no matter how smart the scheduller _is_ > implemented, for the simple reason that hardware > interrupts are hardware interrupts... preemptive or > not, you have to serve them sooner or later and it's > one thing to sever 1 instead of n... another issue > is > reliability. if you use software raid, and the > kernel > goes down (for unrelated reasons) your parity > calculations and the raid cache go down as well, > huh? > and the other way around... the raid goes down, > taking > the sata driver with him... that takes the whole > system down, huh? well, maybe i am too pesimistic > but > still, the scalability concern remains! nics are > huge > scheduller enamies... they have to do so much with > cpu, and transfers to system memory, in order to > actually server thier purpose (protocols) it seams > to > me that there isn't much left for user-land and > software raid... (especially when many nics and many > satas are involved...) > > in short, could you recommend me a peformant (sata > connectors) raid controller, which is fully > supported? > please don't go like "make gconfig" cause i've been > there... thanks! > > regards, > daniel > > > > __________________________________ > Yahoo! Mail - PC Magazine Editors' Choice 2005 > http://mail.yahoo.com > - > To unsubscribe from this list: send the line > "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at > http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
__________________________________ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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