From owner-freebsd-questions@FreeBSD.ORG Sat Feb 12 15:50:51 2011 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 207E510657CD for ; Sat, 12 Feb 2011 15:50:51 +0000 (UTC) (envelope-from amvandemore@gmail.com) Received: from mail-fx0-f54.google.com (mail-fx0-f54.google.com [209.85.161.54]) by mx1.freebsd.org (Postfix) with ESMTP id 9D1C38FC2D for ; Sat, 12 Feb 2011 15:50:50 +0000 (UTC) Received: by fxm16 with SMTP id 16so4006702fxm.13 for ; Sat, 12 Feb 2011 07:50:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=C9FR3TIgyqq9myNL3jmSvaOmHMiR04nI0g83mq7qLoc=; b=YlMjlTPP5aMFBfNbNyfk3Fc79oav6Iiub+GO3cEjcMFUGpzRFS3hRyXtol2LvZr5Sp I/PaFzrZjOWAKF2pz7Rm4xOh7Yei5JlT4lbIqkQW9GFg4YdjYknQny7qOvkqwc5yULl+ TnN1maSz9Tm8HEqkED7A+wenPG3gKQXV3gmiw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=EwPyP88Augd/zPDQERiCRCn0c2nM+IgUeAU3isNWKzvAJi2XH1Jzow1inztlNGWDO8 7IhSdxRt04V+itglR+2lZ6WMsy/FLwHb6+mYz21BxXBFmgILW62K22XaWuM4KoGO3mtq nncgSxVUJtB3F4Gvja3RasuhkMGX5vDdiw+/8= MIME-Version: 1.0 Received: by 10.223.97.2 with SMTP id j2mr2039893fan.23.1297525849358; Sat, 12 Feb 2011 07:50:49 -0800 (PST) Received: by 10.223.94.67 with HTTP; Sat, 12 Feb 2011 07:50:49 -0800 (PST) In-Reply-To: <4D56799D.13036.2335C99A@dave.g8kbv.demon.co.uk> References: <4D550415.8060105@ifdnrg.com> <20110211185738.GB45708@guilt.hydra> <4D56799D.13036.2335C99A@dave.g8kbv.demon.co.uk> Date: Sat, 12 Feb 2011 09:50:49 -0600 Message-ID: From: Adam Vande More To: Dave Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-questions@freebsd.org Subject: Re: FreeBSD and SSD drives X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 12 Feb 2011 15:50:51 -0000 On Sat, Feb 12, 2011 at 6:14 AM, Dave wrote: > Define "a *lot*". If you look up the spec's on the common (currently) > available SSD systems, it's only in the 10's of 1000's writes. Pittiful > compared to magnetic media. > Chances are on many setups, by the time you've written enough data to significantly wear out the drive your magnetic media would died of mechanical failure long before. Purchase what you need MLC/SLC. > The way they work too, if you write one "sector" you actualy re-write a > much larger block of memory. Depends on full setup, the write amplification effect on the X-25's is about 1.1x. Recent SSD's all are much more efficient compared to when these were large, legitimate concerns. > Wear leveling, not that common with SSD > Hard Drives, but very common with USB (Flash) memory sticks, > Completely wrong even the first gen modern SSD's had wear leveling built in. > SSD's have a place, but not for things like swapfiles or working data > that changes a lot.. > I guess ZIL's wouldn't be a good use for such devices either. Perhaps you can inform FS designers that they are doing it wrong. -- Adam Vande More