Messages in this thread | | | Date | Thu, 02 May 2002 22:18:33 +0200 | From | Martin Dalecki <> | Subject | Re: IDE hotplug support? |
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Uz.ytkownik Jakob Østergaard napisa?: > On Thu, May 02, 2002 at 09:26:38PM +0100, Alan Cox wrote: > >>>>=20 >>>>8 x 130MBy/s >>>> PCI bus throughput... I would rather recommend >>>>a classical RAID controller card for this kind of >>>>setup. >>> >>>Because RAID controllers do not use the PCI bus ??? ;) >> >>The raid card transfers the data once, software raid once per device for >>Raid 1/5 - thats a killer. > > > For RAID-1 it's a killer (for writes), I agree. > > But I really doubt it would be so horrible for RAID-5 - after all, it's only > one extra block (the parity block) for each N-1 blocks written (for an N disk > RAID-5). The penalty should be less, the more disks you have in the array. > > But seriously, has anyone out there ever seen a hardware RAID controller with > a *sustained* RAID-5 thoughput of more than 60 MB/sec ? Not that I think it > is impossible, but I've never heard about it. Enlighten me, please, and not > with marketing numbers...
Go to Sun hardware and you will see it quite frequently even on a simple E450 equipped with an external RAID box. I saw them frequently enough in sar accounts when the system was configured to trash on a swap partition, which resided on such a RAID.
64 bit buses win here by a huge margin.
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