Date: Fri, 2 Jan 2004 11:13:46 -0600 From: Jason Bacon <jbacon@mcw.edu> To: Francisco Reyes <lists@natserv.com>, Scott Mitchell <scott+freebsd@fishballoon.org> Cc: freebsd-questions@freebsd.org Subject: Re: What do you use? Message-ID: <200401021113.46323.jbacon@mcw.edu> In-Reply-To: <20040101130752.V65501@zoraida.natserv.net> References: <3FF31E4B.1070305@edgefocus.com> <20040101114640.GB675@tuatara.fishballoon.org> <20040101130752.V65501@zoraida.natserv.net>
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On Thursday 01 January 2004 07:09 am, Francisco Reyes wrote: > On Thu, 1 Jan 2004, Scott Mitchell wrote: > > As for RAID, we use Vinum, but only because I inherited a bunch of > > machines with hot-swap SCSI bays and no hardware RAID. It works well, > > once you have it set up, and I've even managed to swap out failed drives > > without a reboot > > > > :-) I'll definitely investigate the 3ware cards when I need to build a > > : new > > > > RAID server, though. > > But wouldn't a 3ware RAID be slower than an SCSI setup? Unless your > current setup is using old SCSI disks. Also how is the load? Lots of > simultaneous use or just many quick/small access (ie people using > documents/spreadsheets). Well, I'm in a position to provide some comparison data with not-too-many variables, so I felt obliged to run a quick benchmark. The program writes a large file (large enough to overwhelm any memory buffering) using low-level I/O, does an fsync() before closing, and then tests random seek and sequential read on the same file. I watched the system load using top during the benchmark and took a snapshot near the beginning and end of the write cycle. ~~~~~ 3ware Escalade IDE 560gig RAID-5 (8 x 80G barracuda disks): Writing 1677721600 byte test file... Done. Time = 58.433367 Performing 1000 random seeks and reads... Done. Time = 0.235705 Performing sequential read... Done. Time = 7.303429 CPU states: 0.8% user, 0.0% nice, 17.1% system, 0.0% interrupt, 82.2% idle Mem: 68M Active, 609M Inact, 279M Wired, 89M Cache, 112M Buf, 960M Free Swap: 4081M Total, 240K Used, 4081M Free CPU states: 0.4% user, 0.0% nice, 13.2% system, 0.0% interrupt, 86.4% idle Mem: 68M Active, 1390M Inact, 279M Wired, 88M Cache, 112M Buf, 180M Free Swap: 4081M Total, 240K Used, 4081M Free ~~~~~ ICP Vortex SCA 240gig RAID-5 (4 x 72 gig cheetah SCA disks): Writing 1677721600 byte test file... Done. Time = 53.667167 Performing 1000 random seeks and reads... Done. Time = 0.220799 Performing sequential read... Done. Time = 5.114555 CPU states: 0.4% user, 0.0% nice, 9.6% system, 1.0% interrupt, 89.1% idle Mem: 52M Active, 401M Inact, 274M Wired, 77M Cache, 112M Buf, 1201M Free Swap: 4081M Total, 248K Used, 4081M Free CPU states: 0.4% user, 0.0% nice, 25.1% system, 1.9% interrupt, 72.6% idle Mem: 52M Active, 1601M Inact, 276M Wired, 74M Cache, 112M Buf, 3228K Free Swap: 4081M Total, 248K Used, 4081M Free Both systems are running 5.1-RELEASE, with 2 gig RAM. The 3ware machine has a faster CPU (Athlon 1.6Ghz) than the ICP (dual Pentium 850), but this shouldn't be significant for raw I/O at these CPU speeds. The CPU usage is lower on the ICP system (remember that it has a slower CPU when comparing the CPU loads). CPU use consistently went up toward the end of the write cycle on the ICP system, but stayed flat on the 3ware. I noticed a drastic reduction of CPU load on the 3ware system when we went from 4.5-RELEASE to 4.6-RELEASE CPU load has never been a problem on either server. JB
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