Date: Tue, 11 Sep 2007 22:00:44 -0700 From: "Jeff Mohler" <speedtoys.racing@gmail.com> To: "Mike Sweetser - Adhost" <mikesw@adhost.com> Cc: freebsd-questions@freebsd.org Subject: Re: Best SCSI or SAS RAID for a NAS? Message-ID: <a969fbd10709112200r41e11f5fn57464e9a0c9a9a80@mail.gmail.com> In-Reply-To: <17838240D9A5544AAA5FF95F8D5203160279A3C0@ad-exh01.adhost.lan> References: <17838240D9A5544AAA5FF95F8D5203160279A27B@ad-exh01.adhost.lan> <20070911182712.H3142@wojtek.tensor.gdynia.pl> <17838240D9A5544AAA5FF95F8D5203160279A3C0@ad-exh01.adhost.lan>
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Tell us what your workload IS..that will help a lot. Its not necessarily MB/sec, but disk IO's per second. Such as..if you have 5 servers with applications creating 100 IOPS on the local drive, then you need a RAID array capable of at least 500 IOPS at under 20ms to remain happy with it. You can expect up to 180 IOPS under 20ms on 15k drives, and 100-120 on 10k drives (or thereabouts) to also remain under 20ms per random IO. Notably, the overhead of the raid layout will factor into this as well. Tell us what your load will be, then you can get reasonable configuration guidelines. On 9/11/07, Mike Sweetser - Adhost <mikesw@adhost.com> wrote: > > Thanks for the replies, everybody. > > > Its not just the controller you should be checking. > > The drives RPM speed, how many drives in the array, > > are you using RAID 0+1 or just RAID 5 for the array. > > Could you give more details on these issues? > > The array's running RAID 10 with basically the minimum drives for RAID > 10; drives are 15K SCSI. I'd think this would be enough. > > > no RAID controller, lots of cheap disks and thinking > > about how to RIGHT set UP gmirror/gstripe/gconcat will > > give you best performance. > > The concern is that this array is mounted over NFS by a number of > different servers, all with constant read/write, so this is why we need > throughput as high as we can get. Right now, we're only getting a > fraction of the performance we theoretically should be getting. > > Mike Sweetser > > -------------------------- > Mike Sweetser | Systems Administrator > > Adhost Internet > 140 Fourth Avenue North, Suite 360, Seattle, Washington 98109 USA > P 206.404.9023 T 888.234.6781 (ADHOST-1) F 206.404.9050 > E mikesw@adhost.com W adhost.com > > Our brand new Adhost West data center is open - contact us for a tour at > 1-888-234-6781 (ADHOST-1) > > -----Original Message----- > From: owner-freebsd-questions@freebsd.org > [mailto:owner-freebsd-questions@freebsd.org] On Behalf Of Wojciech > Puchar > Sent: Tuesday, September 11, 2007 9:28 AM > To: Mike Sweetser - Adhost > Cc: freebsd-questions@freebsd.org > Subject: Re: Best SCSI or SAS RAID for a NAS? > > > We're looking for opinions on what the best RAID controller would be > for > > no RAID controller, lots of cheap disks and thinking about how to RIGHT > set UP gmirror/gstripe/gconcat will give you best performance. > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to > "freebsd-questions-unsubscribe@freebsd.org" > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > freebsd-questions-unsubscribe@freebsd.org" >
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