From owner-freebsd-questions@FreeBSD.ORG Sun May 26 23:40:19 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id C5FE7CCE for ; Sun, 26 May 2013 23:40:19 +0000 (UTC) (envelope-from kudzu@tenebras.com) Received: from mail-ob0-x233.google.com (mail-ob0-x233.google.com [IPv6:2607:f8b0:4003:c01::233]) by mx1.freebsd.org (Postfix) with ESMTP id 91F5929B for ; Sun, 26 May 2013 23:40:19 +0000 (UTC) Received: by mail-ob0-f179.google.com with SMTP id wo10so3971889obc.10 for ; Sun, 26 May 2013 16:40:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:x-gm-message-state; bh=B07FUSHooJxvsvtVQ7b1XVY21iIeAMicN1qP6dXkxiE=; b=IhEL0dq9bx7K1OsC7BaoKWBVVFwpg4B0ShaS+oFXGHIFWovsKHnw1Qb0kh/gDoHmSl MElT0kbmUezwz6Z7S4EFWTHMdnPLxRfJ8vryDzcZGKd/YC3KdtL7iTAF6JJ5Pp6gLW/L DLKoUI6EbZ/j6ITxTSx+vdBL4J+yIAQ0deMd/kgn2+bE8PvxwQRUo7JBlNSdlsFIbssI HDH9/I/8k1fp1AM8ZEO84E6kGARlQnODDLVrYH3XXjfyv47Ln7+VbYDWRLkB57zQntYW tYOcUWv7Ry82tpHxahxEcTxLOTrw//cy+2WEPtlgMszPje2yHsc04+a3pw/hEwG8wsCV rlKw== MIME-Version: 1.0 X-Received: by 10.60.125.201 with SMTP id ms9mr16902171oeb.65.1369611618063; Sun, 26 May 2013 16:40:18 -0700 (PDT) Received: by 10.60.9.99 with HTTP; Sun, 26 May 2013 16:40:18 -0700 (PDT) In-Reply-To: References: <1369558712.96152.YahooMailNeo@web165006.mail.bf1.yahoo.com> <20130526160906.4e379016@X220.ovitrap.com> <20130526113235.f5dbe768.freebsd@edvax.de> Date: Sun, 26 May 2013 16:40:18 -0700 Message-ID: Subject: Re: "swap" partition leads to instability? From: Michael Sierchio To: Warren Block X-Gm-Message-State: ALoCoQkLX9lubLGSrNUGfh41kjRY5B2iVnV/OKWq9HJPeyS2ZJNweQSKRdk5qHxDdn7C0ik+cM0H Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: Erich Dollansky , Polytropon , "freebsd-questions@freebsd.org" , "M. V." X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 26 May 2013 23:40:19 -0000 The Intel SLC mSATA drives I use in embedded devices don't support TRIM, but - it doesn't seem to matter. Actually, I'm confident that just using bare partitions for swap is fine, and I haven't had any of the trouble I witnessed with MLC devices. The difference is that the size is limited to under 32GB. - M On Sun, May 26, 2013 at 4:32 PM, Warren Block wrote: > On Sun, 26 May 2013, Polytropon wrote: > > On Sun, 26 May 2013 16:09:06 +0700, Erich Dollansky wrote: >> >>> Hi, >>> >>> On Sun, 26 May 2013 01:58:32 -0700 (PDT) >>> "M. V." wrote: >>> >>> I have a 24/7 network server/gateway with FreeBSD-8.2 on a SSD drive. >>>> it's partitioned as normal (/ , /tmp, /var , /usr and swap) for a >>>> long time now. But recently I heard from a FreeBSD expert that I >>>> shouldn't have swap partition for my server, and having swap >>>> partition could make my server unstable. this was so strange for me, >>>> and I searched a lot but couldn't find a reason for this claim. >>>> >>>> because it is a false claim. I never ever have had any system with >>> working hard, that gave a problem because of the swap space. >>> >> >> I think the "problem" here is that he's using a SSD. >> As soon as the swap partition is being in heavy use, >> which means it receives many writes, this may lead >> to the SSD "wearing out", decreasing its lifetime. >> > > Another problem with SSDs is that they can have difficulty with wear > leveling. This is even worse with swap because there is no way to use TRIM > to tell the SSD about blocks that have been freed. > > The workaround is a swapfile on UFS with TRIM enabled. It works fine, and > even better when you update the rc scripts for shutdown. > > Here's an article on setup: > http://www.wonkity.com/~**wblock/docs/html/ssd.html > > And here is the PR with a patch: > http://www.freebsd.org/cgi/**query-pr.cgi?pr=bin/168544 > > ______________________________**_________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/**mailman/listinfo/freebsd-**questions > To unsubscribe, send any mail to "freebsd-questions-** > unsubscribe@freebsd.org " >