From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 84EF013877A for ; Thu, 4 Sep 2014 19:07:44 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 8A4BBE09E8; Thu, 4 Sep 2014 19:07:36 +0000 (UTC) Received: from mail-vc0-f196.google.com (mail-vc0-f196.google.com [209.85.220.196]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 75CA7E09C3 for ; Thu, 4 Sep 2014 19:07:35 +0000 (UTC) Received: by mail-vc0-f196.google.com with SMTP id id10so3627126vcb.7 for ; Thu, 04 Sep 2014 12:07:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:content-type:content-transfer-encoding; bh=PREYvC5c1iXWiCPUvnruBgXxwpqilaMLwM4bF/v4a7A=; b=UsOqBGVFAnX5dX+5xuOQ6smLar7vF/u+9vMjhLQVc0b3tz4j8bpex/kWQsqjMhfnMs apFOIuLWoGsggBttctq8+VDwTr1p97N/+FfkHRHSH/s+Eq20/9IwCJPhIPff7Iix97JE MxaE/Kzpz5OV3c+7GDoMobG2qK49oGVmxWKh9mT5hUbF0Rufi9ZTPklQJXhCUyNrqo3+ 4dxIONFplbXXtflj0Vfd0uabkQWD3gZLwRypJhcC85crAdBnHl+BdG3A6WbmZDw29MHN lWK/ejS+X9F4I58VJ1u4iiSODXi6/d2NO6XTbo6/FZ3PCjG3qiicziEVTMCVFhiywM9M LUrw== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 X-Received: by 10.220.105.142 with SMTP id t14mr6232743vco.14.1409857654587; Thu, 04 Sep 2014 12:07:34 -0700 (PDT) Sender: freemanrich@gmail.com Received: by 10.52.8.229 with HTTP; Thu, 4 Sep 2014 12:07:34 -0700 (PDT) In-Reply-To: References: <20140904175719.GH7483@syscon7> Date: Thu, 4 Sep 2014 15:07:34 -0400 X-Google-Sender-Auth: 1A9VTlEaAOBc7PjwHPIBvL85aVc Message-ID: Subject: Re: [gentoo-user] SSD discard / fstrim From: Rich Freeman To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Archives-Salt: d03c01ac-4585-4701-8a54-ddee143a865f X-Archives-Hash: eeb262ceb3b54c3c36baf86b3fea8c76 On Thu, Sep 4, 2014 at 2:26 PM, =D0=A1=D0=B5=D1=80=D0=B3=D0=B5=D0=B9 wrote: > You need to run Fstrim if you mounted your partition WITHOUT "discard" > option and did lots of changes. For example, if you installed your > system without "discard", do fstrim and then add "discard" to > /etc/fstab. > Just a note that depending on the SSD model, discard can have a substantial performance penalty with negligible benefit compared to just sticking fstrim in your crontab. In theory the ssd should just handle discard by making a note of what is trimmed and utlizing this information when needed. In practice many ssds handle a trim by dropping whatever they're doing and don't a copy/delete cycle if only part of a block is trimmed, which defeats the whole point of trimming in the first place. FStrim has the advantage of being more asynchronous and possibly being able to consolidate trims over a longer time-period, which could improve performance if the ssd isn't smart about it. Is there a really good place to go for SSD reviews/etc that actually takes this sort of thing into account? After getting an SSD it became apparently that they vary widely in terms of quality. Heck, I can't even tell you what the erase cycle count is from the SMART info, while other models seems to provide all kinds of useful info. -- Rich