From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Megacz Subject: anybody using the gc-ramdisk? Date: Mon, 04 Jan 2010 21:16:51 +0000 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Has anybody tried using the GC-Ramdisk (aka iRAM -- four DDR DIMMs on a PCI card with a battery backup) http://www.gigabyte.com.tw/Products/Storage/Products_Overview.aspx?ProductID=2180 http://en.wikipedia.org/wiki/I-RAM Performance is much better than flash memories, but the price per gigabyte is much greater and maximum capacity is far less. It's really closer to the nvram cache on a hardware raid card than an SSD. The fact that it loses data after 16 hours without power is a little worrisome, although it uses a standard nimh battery so you can replace that with something that lasts a lot longer... Anyways, I'd be interested in hearing about anybody's experience with it. I'm thinking of using this for my md write intent bitmap and ext4 journal, with "-o data=ordered" so close() and fsync() return as soon as the data hits the DIMMs -- no need to wait for the disk to rotate around. Any comments? So often I hear debates about "hardware raid" versus "software raid" which are actually debates over whether or not you ought to have some sort of battery-backed write cache around. - a