Date: Sun, 28 Sep 2008 09:54:36 -0400 From: Bill Moran <wmoran@potentialtech.com> To: "Danny Do" <danhdo@gmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: Hard disk bottle neck. Message-ID: <20080928095436.3c9783c2.wmoran@potentialtech.com> In-Reply-To: <00d101c92154$691f53c0$3b5dfb40$@com> References: <00d101c92154$691f53c0$3b5dfb40$@com>
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"Danny Do" <danhdo@gmail.com> wrote: > > Hi guys, > > I have this problem for years but couldn't find a way to solve it. > > I have a file server handling large files from 1MByte to 1GByte. > > Server Info: > FreeBSD 6.2 > Apache 2.2.9 > > DELL PowerEdge 1850 > 2GB RAM (only 184MB is active) > 6x300MB SCSI 10K RPM RAID5 > Gigabit Ethernet Connection > > My server can output NO MORE than 60Mbps (read only). > > The bottle neck is the hard disk. What evidence do you have that the bottleneck is disk IO? I've seen no evidence, only speculation. In addition to the advice of others, you may be able to just beef up the RAM. 2G isn't much these days. If you've got 200M active, you've got about 1.8G available to cache files. If you have repeated access of the same file, the OS can cache that file data and not even use the disk, but it can only do that if it has enough RAM to work with. You need to get your facts straight, though. According to the specs you've got above, you've only got 1.5G of disk. I expect you meant 300G disks. You could also add disks in a RAID 10, which is generally faster than RAID 5, or move to 15,000 RPM disks. I think you might be surprised how much adding some RAM will help, though, unless your access patterns are very random, RAM should speed up the access of popular data significantly. -- Bill Moran http://www.potentialtech.com
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