From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Moore Subject: Re: Real Time Mirroring of a NAS Date: Tue, 18 Apr 2006 21:23:54 -0700 Message-ID: <4445BB5A.8060201@nsr500.net> References: <44364336.7060704@aol.com> <8110058661.20060407200418@2ka.mipt.ru> <4436984A.9020803@aol.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4436984A.9020803@aol.com> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids andy liebman wrote: > ... > By the way, I use 3ware 9550SX cards. On a 16 drive RAID-5 SATA array, I > can get sequential reads that top 600 MBs/sec. That's megabytes, not > megabits. And write speeds are close to 400 MB/sec with the new faster > on-board XOR processing. And random reads are at least 200 MB/sec. So, > 10 GbE is a must, really. A 400MB/s network input stream means either 1x10GbE or 4xGbE's to PCI-X/PCI-e bus, then to disk, then to PCI-X/PCI-e bus, then across another net to the backup system, so the I/O subsystem alone must handle 800MB/s. 3ware may actually do a single 400MB/s stream, but what about 4x100MB/s or 8x50MB/s? It's really hard to do that much I/O _and_ provide data integrity. If your data rates and the mirroring requirements are that critical you might want to look at the fast NAS systems coming out (eg- agami.com) built on top of AMD's HT architecture. Cheers, > > Andy > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- | for direct mail add "private_" in front of user name