Date: Fri, 20 May 2005 07:25:58 +0200 From: Martin Nilsson <martin@gneto.com> To: Alexis Yushin <alexis@ww.net> Cc: freebsd-performance@freebsd.org Subject: Re: Bad 3ware 9000 performance 5.4? Message-ID: <428D74E6.4010203@gneto.com> In-Reply-To: <20050520031332.GA98548@virgin.ww.net> References: <20050520031332.GA98548@virgin.ww.net>
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Alexis Yushin wrote: > Hi, > > Running FreeBSD 5.4... three machines with twe/3ware 8000 and three twa/ > 3ware 9500-8 controllers. All of them running RAID 1+0 without write cache > since we dont have battery backup unit. All of them Seagate 7200 SATA. > I get about 46Mb/s write on the 8000 series and only 5(!)MB/s on the 9500 series. I have noticed that the MegaRAID SATA cards sometimes disables the write cache on Seagate SATA drives, resulting in a write performance of about 6MB/s. Can you check if the 3ware also does this. I have had arrays were only one disk had write cache disabled and it totally ruined the performance of the whole array. As always be sure to have a good UPS if you are using write cache on the disks! With the sad state of todays ATA/SATA disks turning of write caching in the drive is often not an option. /Martin
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