Date: Wed, 25 Jan 2006 00:44:19 +0300 From: Sergey Lungu <sergey.lungu@gmail.com> To: Eric Anderson <anderson@centtech.com> Cc: freebsd-geom@freebsd.org Subject: Re: GEOM stripe + concat Message-ID: <20060125004419.17dd39b1.sergey.lungu@gmail.com> In-Reply-To: <43D6985A.1030101@centtech.com> References: <20060122192257.273734cf.sergey.lungu@gmail.com> <20060124232443.2e252b87.sergey.lungu@gmail.com> <43D6985A.1030101@centtech.com>
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On Tue, 24 Jan 2006 15:12:58 -0600 Eric Anderson <anderson@centtech.com> wrote: > Sergey Lungu wrote: > > On Sun, 22 Jan 2006 19:22:57 +0300 I wrote: > > > > > >> Hello, > >> > >> I have FreeBSD 6.0-RELEASE running on my FTP server. There are > >> three disks on that box: two identical 120GB and one 300GB. I am > >> using gvinum for stripping between first two disks. I am going to > >> give gstripe a try, sine gvinum is too unstable. > >> > > > > Since nobody has answered my question, possibly it was too silly, I > > decided to experiment a bit. I'll answer my questions: > > > > > >> Am I able to concatenate created stripe with 300GB disk? > >> > > > > Yes, you can! > > > > > >> And is it wise at all? > >> > > > > I have made some simple benchmarking on three different geometries. > > Legend: > > a * b - stripping between a and b > > a + b - concatenation of a and b > > ad1 - 120GB disk > > ad2 - 120GB disk > > ad3 - 300GB disk > > > > I tried to upload and then download a 700MB movie. Here are my > > results: > > > > ad1 * ad2: > > Uploading: 1m8.406s > > Downloading: 1m4.656s > > > > ad1 * ad2 + ad3: > > Uploading: 1m4.115s > > Downloading: 1m4.962s > > > > ad1 + ad2 + ad3: > > Uploading: 1m4.110s > > Downloading: 1m4.971s > > > > Conclusion: > > There is no big difference between all this geometries in FTP > > context, or possibly there are some on high load!? > > > > I'm not sure the details of your tests, since 'upload and then > download' doesn't really explain the test, however I'm guessing you > were limited by network or the destination rather than the local disk > - 1m 4s looks alot like 100mbit to me. Yes, we have 100mbit network. > You should try one of the many benchmarking tools as a first start > (try iozone, or bonnie, etc). I'm not interested in real disk performance, since this box is used only for ftp. Probably I was wrong from the begining and I am limited only by the network speed, so software RAID is not the right way to boost our ftp server :) > Also, concat won't give you any performance increase, but striping > could. You could easily test your 700mb file by doing something like > this: > > dd if=/path/to/700mb-file of=/dev/null bs=1m I don't think that stripping between two disks can give some significant performance boost (I may be wrong, of course), especially in ftp context. I think I'll use a*b+c geometry, but the question is: Will I have the same problems with gstripe+gconcat as with gvinum? :) Thanks for the answer. -- Sergey Lungu The deficiency will never show itself during the test runs.
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