From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, HTML_MESSAGE,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 12543 invoked from network); 6 Mar 2021 01:52:53 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 6 Mar 2021 01:52:53 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id AFCA29CAA8; Sat, 6 Mar 2021 11:52:49 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 3C4739CA6D; Sat, 6 Mar 2021 11:52:20 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=bsdimp-com.20150623.gappssmtp.com header.i=@bsdimp-com.20150623.gappssmtp.com header.b="Xv6nfWud"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id E48769CA6D; Sat, 6 Mar 2021 11:52:16 +1000 (AEST) Received: from mail-qk1-f182.google.com (mail-qk1-f182.google.com [209.85.222.182]) by minnie.tuhs.org (Postfix) with ESMTPS id E9F3C9CA6B for ; Sat, 6 Mar 2021 11:52:15 +1000 (AEST) Received: by mail-qk1-f182.google.com with SMTP id z190so3981850qka.9 for ; Fri, 05 Mar 2021 17:52:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=+izH07ucCwPEAqwPx4c0pXgJHD5kH4lx7ewXTaWPepY=; b=Xv6nfWudj3hrjSEWQDspv0AQLhT9MxyaOJxlWlvPJ20gEpN6HsyiLVjj8Fh/sXg0m5 VRGW/M2UBe762b9zqhMVpmFiPLjaTspDZKZZPEWaPSCka/5ZNL1ev2MvqKr8P2499SHO oDz/9+0eRS/m5bnB6Bw+eWKErfU2hFDTNSb2/YsZPRbKbrvqxvhjUvAB7TDjPAWb8zZd 8ftpXNdpZri3LJeYAv1SCbi4c6USWY1BC6arDxea3x4Zp0GHpEVhJj7eqHdy/G6GLt+n eiqi0ZVxsNs2QirYI6xVVqpkpkPoUmJ3xwL3sLJQL86ZxcrEAd2mEGG1zI0dsZpxRO02 PlIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=+izH07ucCwPEAqwPx4c0pXgJHD5kH4lx7ewXTaWPepY=; b=GbvFH3kbbYciaDK2drOXns6AK/oXQ3LAXnu+adOdT5ZuqQ6Qk5+Wh51l7v4EHDAvSK mXQL7bgjURSN3BVSnsUr/tuvFOYHa8q9IIjwniH2l9dIaQQdE6cQg5LGVdZnAqGkGEUb dEFRhdnGssu2LrLDdVmzIckRaD00pom/c1nr40ckcPuqjb8IxUHiia3b0V8KHewEnkS/ w8NTZQKKoKvkxZ5LniOSrn/ru9xk+JuGv1KZ9egGlgLU0gVIhhvocDqtR60fsDHVU/S5 BTo3AOA6bNwgGtLJXxKnRTDcPKry2kcKcdiFEl1AcRZL1kJVZvVy2W4/GSDikGHwy+O/ 4YYA== X-Gm-Message-State: AOAM532mXn6bXw6X/P/49d0YJEgrr8foDtBGOtC1g099d1KuxpXLnxgr VdNw9HEUbPdKfEYuQXX2E4EcX79dmqVxIAwrrpaYZA== X-Google-Smtp-Source: ABdhPJwA560W1nltDplcfJP0uIiNg2S++U8pV3LQ5+NsjdRcuZWLkfMSHbzyBNpgYff+XBAvlvOw0Gm+YJUd4Ooamw4= X-Received: by 2002:a37:a085:: with SMTP id j127mr11381292qke.206.1614995534874; Fri, 05 Mar 2021 17:52:14 -0800 (PST) MIME-Version: 1.0 References: <20210304212459.GA6303@eureka.lemis.com> <20210304212917.GB6303@eureka.lemis.com> <25189.1614937832@hop.toad.com> <20210306011824.GB80491@eureka.lemis.com> In-Reply-To: <20210306011824.GB80491@eureka.lemis.com> From: Warner Losh Date: Fri, 5 Mar 2021 18:52:02 -0700 Message-ID: To: "Greg 'groggy' Lehey" Content-Type: multipart/alternative; boundary="0000000000002b9c4805bcd4731d" Subject: Re: [TUHS] tunefs -m 5% X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: TUHS main list Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --0000000000002b9c4805bcd4731d Content-Type: text/plain; charset="UTF-8" On Fri, Mar 5, 2021, 6:18 PM Greg 'groggy' Lehey wrote: > On Friday, 5 March 2021 at 10:32:15 -0500, Theodore Ts'o wrote: > > On Fri, Mar 05, 2021 at 01:50:32AM -0800, John Gilmore wrote: > >> John P. Linderman wrote: > >>> I have several 12 TB disks scattered about my house. 5% of 12TB is > 600GB. > >> > >> At one point in hystery, ext2 performance was reported to suffer badly > >> if there was less than 5% of disk space available in an active > >> filesystem. My naive belief, probably informed by older and wiser heads > >> around Sun, was that when the file system was >95% full, ext2 spent a > >> lot of time seeking around in free lists finding single allocatable > >> blocks. And there were no built-in "defragmentation" programs that > >> could easily fix that. > > > > I'll point out that BSD FFS, at least in BSD 4.3, reserves 10% of the > > file system for reserved blocks. > > Oops, that's what I get for reading messages sequentially :-( But in > this case it's for small values of 10. > We set this to 1% at Netflix and fill to about ~98-99% full over UFS. This works well as we don't have small files. SATA Flash we keep a bit more empty, but that's due to its crappy FLT liking more free space... Warner Greg > -- > Sent from my desktop computer. > Finger grog@lemis.com for PGP public key. > See complete headers for address and phone numbers. > This message is digitally signed. If your Microsoft mail program > reports problems, please read http://lemis.com/broken-MUA > --0000000000002b9c4805bcd4731d Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Fri, Mar 5, 2021, 6:18 PM Greg 'groggy' Leh= ey <grog@lemis.com> wrote:
<= /div>
On Friday,=C2=A0 5 March 2021 at 10:32:= 15 -0500, Theodore Ts'o wrote:
> On Fri, Mar 05, 2021 at 01:50:32AM -0800, John Gilmore wrote:
>> John P. Linderman <jpl.jpl@gmail.com> wrote:
>>> I have several 12 TB disks scattered about my house. 5% of 12T= B is 600GB.
>>
>> At one point in hystery, ext2 performance was reported to suffer b= adly
>> if there was less than 5% of disk space available in an active
>> filesystem.=C2=A0 My naive belief, probably informed by older and = wiser heads
>> around Sun, was that when the file system was >95% full, ext2 s= pent a
>> lot of time seeking around in free lists finding single allocatabl= e
>> blocks.=C2=A0 And there were no built-in "defragmentation&quo= t; programs that
>> could easily fix that.
>
> I'll point out that BSD FFS, at least in BSD 4.3, reserves 10% of = the
> file system for reserved blocks.

Oops, that's what I get for reading messages sequentially :-(=C2=A0 But= in
this case it's for small values of 10.

We set this to 1% at Netflix and = fill to about ~98-99% full over UFS. This works well as we don't have s= mall files. SATA Flash we keep a bit more empty, but that's due to its = crappy FLT liking more free space...

Warner=C2=A0

Greg
--
Sent from my desktop computer.
Finger grog@lemis.com for PGP public key.
See complete headers for address and phone numbers.
This message is digitally signed.=C2=A0 If your Microsoft mail program
reports problems, please read http://lemis.com/broken-MUA
--0000000000002b9c4805bcd4731d--