From mboxrd@z Thu Jan 1 00:00:00 1970 From: kedacomkernel Subject: Re: Re: mkfs.xfs states log stripe unit is too large Date: Mon, 9 Jul 2012 20:02:28 +0800 Message-ID: <201207092002243437160@gmail.com> References: <20120623234445.GZ19223@dastard> <4FE67970.2030008@sandeen.net> <4FE710B7.5010704@hardwarefreak.com> <20120626023059.GC19223@dastard> <20120626080217.GA30767@infradead.org> <20120702061827.GB16671@infradead.org> <20120702164113.109162be@notabene.brown>, <20120702080802.GQ19223@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: base64 Return-path: Sender: linux-raid-owner@vger.kernel.org To: Dave Chinner , Neil Brown Cc: Christoph Hellwig , Ingo J?rgensmann , xfs , linux-raid List-Id: linux-raid.ids T24gMjAxMi0wNy0wMiAxNjowOCBEYXZlIENoaW5uZXIgPGRhdmlkQGZyb21vcmJpdC5jb20+IFdy b3RlOg0KPk9uIE1vbiwgSnVsIDAyLCAyMDEyIGF0IDA0OjQxOjEzUE0gKzEwMDAsIE5laWxCcm93 biB3cm90ZToNCj4+IE9uIE1vbiwgMiBKdWwgMjAxMiAwMjoxODoyNyAtMDQwMCBDaHJpc3RvcGgg SGVsbHdpZyA8aGNoQGluZnJhZGVhZC5vcmc+IHdyb3RlOg0KPj4gDQo+PiA+IFBpbmcgdG8gTmVp bCAvIHRoZSByYWlkIGxpc3QuDQo+PiANCj4+IFRoYW5rcyBmb3IgdGhlIHJlbWluZGVyLg0KPj4g DQo+PiA+IA0KW3NuaXBdDQo+DQo+VGhhdCdzIHRydWUsIGJ1dCB0aGUgY2hhcmFjdGVyaXNpdGlj cyBvZiBzcGlubmluZyBkaXNrcyBoYXZlIG5vdA0KPmNoYW5nZWQgaW4gdGhlIHBhc3QgMjAgeWVh cnMsIG5vciBoYXMgdGhlIHR5cGljYWwgZmlsZSBzaXplDQo+ZGlzdHJpYnV0aW9ucyBpbiBmaWxl c3lzdGVtcywgbm9yIGhhdmUgdGhlIFJBSUQ1LzYgYWxnb3JpdGhtcy4gU28NCj5pdCdzIG5vdCBy ZWFsbHkgY2xlYXIgdG8gbWUgd2h5IHlvdTtkIHdvdWwgZGV2ZW4gY29uc2lkZXIgY2hhbmdpbmcN Cj50aGUgZGVmYXVsdCB0aGUgZG93bnNpZGVzIG9mIGxhcmdlIGNodW5rIHNpemVzIG9uIFJBSUQ1 LzYgdm9sdW1lcyBpcw0KPndlbGwga25vd24uIFRoaXMgbWF5IHdlbGwgZXhwbGFpbiB0aGUgYXBw YXJlbnQgaW5jcmVhc2UgaW4gIlhGUyBoYXMNCj5odW5nIGJ1dCBpdCdzIHJlYWxseSBqdXN0IHdh aXRpbmcgZm9yIGxvdHMgb2YgcmVhbGx5IHNsb3cgSU8gb24gTUQiDQo+Y2FzZXMgSSd2ZSBzZWVu IG92ZXIgdGhlIHBhc3QgY291cGxlIG9mIHllYXJzLg0KPg0KQXQgcHJlc2VudCwgY2F0IC9zeXMv YmxvY2svc2RiL3F1ZXVlL21heF9zZWN0b3JzX2tiOg0KaXMgNTEyay4gTWF5YmUgYmVjYXVzZSB0 aGlzLg0KDQo+VGhlIG9ubHkgdGltZSBJJ2QgZXZlciBjb25zaWRlciBzdHJpcGUgLXdpZHRocy0g b2YgbW9yZSB0aGFuIDUxMmsgb3INCj4xTUIgd2l0aCBSQUlENS82IGlzIGlmIEkga25ldyBteSB3 b3JrbG9hZCBpcyBhbG1vc3QgZXhjbHVzaXZlbHkNCj51c2luZyBsYXJnZSBmaWxlcyBhbmQgc2Vx dWVudGlhbCBhY2Nlc3Mgd2l0aCBsaXR0bGUgbWV0YWRhdGEgbG9hZCwNCj5hbmQgdGhlcmUncyBy ZWxhdGl2ZWx5IGZldyB3b3JrbG9hZHMgd2hlcmUgdGhhdCBpcyB0aGUgY2FzZS4NCj5UeXBpY2Fs bHkgdGhvc2Ugd29ya2xvYWRzIG1lYXN1cmUgdGhyb3VnaHB1dCBpbiBHQi9zIGFuZCBldmVyeW9u ZQ0KPnVzZXMgaGFyZHdhcmUgUkFJRCBmb3IgdGhlbSBiZWNhdXNlIE1EIHNpbXBseSBkb2Vzbid0 IHNjYWxlIHRvIHRoaXMNCj5zb3J0IG9mIHVzYWdlLg0KPg0KPj4gSWYgNTEySyBpcyBhbHdheXMg c3Vib3B0aW1hbCBmb3IgWEZTIHRoZW4gdGhhdCBpcyB1bmZvcnR1bmF0ZSBidXQgSSBkb24ndA0K Pg0KPkkgdGhpbmsgNTEyayBjaHVuayBzaXplcyBhcmUgc3Vib3B0aW1hbCBmb3IgbW9zdCB1c2Vy cywgcmVnYXJkbGVzcw0KPm9mIHRoZSBmaWxlc3lzdGVtIG9yIHdvcmtsb2FkLi4uLg0KPg0KPj4g dGhpbmsgaXQgaXMgcmVhbGx5IHBvc3NpYmxlIHRvIGNob29zZSBhIGRlZmF1bHQgdGhhdCBldmVy eW9uZSB3aWxsIGJlIGhhcHB5DQo+PiB3aXRoLiAgTWF5YmUgd2UganVzdCBuZWVkIG1vcmUgZG9j dW1lbnRhdGlvbiBhbmQgd2FybmluZyBlbWl0dGVkIGJ5IHZhcmlvdXMNCj4+IHRvb2xzLiAgTWF5 YmUgbWtmcy54ZnMgY291bGQgYXVnbWVudCB0aGUgInN0cmlwZSB1bml0IHRvbyBsYXJnZSIgbWVz c2FnZSB3aXRoDQo+PiBzb21lIHRleHQgYWJvdXQgY2hvb3NpbmcgYSBzbWFsbGVyIGNodW5rIHNp emU/DQo+DQo+V2Ugd29yayB0byB0aGUgbWFudHJhIHRoYXQgWEZTIHNob3VsZCBhbHdheXMgY2hv b3NlIHRoZSBkZWZhdWx0cw0KPnRoYXQgZ2l2ZSB0aGUgYmVzdCBvdmVyYWxsIHBlcmZvcm1hbmNl IGFuZCBhZ2luZyBjaGFyYWN0ZXJpc3RpY3Mgc28NCj51c2VycyBkb24ndCBuZWVkIHRvIGJlIGEg c3RvcmFnZSBleHBlcnQgdG8gZ2V0IHRoZSBiZXN0IHRoZQ0KPmZpbGVzeXN0ZW0gY2FuIG9mZmVy LiBUaGUgWEZTIHdhcm5pbmcgaXMgdGhlcmUgdG8gaW5kaWNhdGUgdGhhdCB0aGUNCj51c2VyIG1p Z2h0IGJlIGRvaW5nIHNvbWV0aGluZyB3cm9uZy4gSWYgdGhhdCdzIGJlaW5nIGVtaXR0ZWQgd2l0 aCBhDQo+ZGVmYXVsdCBNRCBjb25maWd1cmF0aW9uLCB0aGVuIHRoYXQgaW5kaWNhdGVzIHRoYXQg dGhlIE1EIGRlZmF1bHRzDQo+bmVlZCB0byBiZSByZXZpc2VkLi4uLg0KPg0KPklmIHlvdSBrbm93 IHdoYXQgYSBzdHJpcGUgdW5pdCBvciBjaHVuayBzaXplIGlzLCB0aGVuIHlvdSBrbm93IGhvdw0K PnRvIGRlYWwgd2l0aCB0aGUgcHJvYmxlbS4gQnV0IGZvciB0aGUgbWFqb3JpdHkgb2YgcGVvcGxl LCB0aGF0J3Mgd2F5DQo+bW9yZSBrbm93bGVkZ2UgdGhhbiB0aGV5IGFyZSBwcmVwYXJlZCB0byBs ZWFybiBhYm91dCBvciBzaG91bGQgYmUNCj5mb3JjZWQgdG8gbGVhcm4gYWJvdXQuDQo+DQo+Q2hl ZXJzLA0KPg0KPkRhdmUuDQo+LS0gDQo+RGF2ZSBDaGlubmVyDQo+ZGF2aWRAZnJvbW9yYml0LmNv bQ0KPi0tDQo+VG8gdW5zdWJzY3JpYmUgZnJvbSB0aGlzIGxpc3Q6IHNlbmQgdGhlIGxpbmUgInVu c3Vic2NyaWJlIGxpbnV4LXJhaWQiIGluDQo+dGhlIGJvZHkgb2YgYSBtZXNzYWdlIHRvIG1ham9y ZG9tb0B2Z2VyLmtlcm5lbC5vcmcNCj5Nb3JlIG1ham9yZG9tbyBpbmZvIGF0ICBodHRwOi8vdmdl ci5rZXJuZWwub3JnL21ham9yZG9tby1pbmZvLmh0bWw= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q69C1TYF222469 for ; Mon, 9 Jul 2012 07:01:29 -0500 Received: from mail-pb0-f53.google.com (mail-pb0-f53.google.com [209.85.160.53]) by cuda.sgi.com with ESMTP id T92VxgLp0gHD9t0Y (version=TLSv1 cipher=RC4-SHA bits=128 verify=NO) for ; Mon, 09 Jul 2012 05:01:28 -0700 (PDT) Received: by pbbrr13 with SMTP id rr13so23859026pbb.26 for ; Mon, 09 Jul 2012 05:01:28 -0700 (PDT) Date: Mon, 9 Jul 2012 20:02:28 +0800 From: kedacomkernel Subject: Re: Re: mkfs.xfs states log stripe unit is too large References: <20120623234445.GZ19223@dastard> <4FE67970.2030008@sandeen.net> <4FE710B7.5010704@hardwarefreak.com> <20120626023059.GC19223@dastard> <20120626080217.GA30767@infradead.org> <20120702061827.GB16671@infradead.org> <20120702164113.109162be@notabene.brown>, <20120702080802.GQ19223@dastard> Mime-Version: 1.0 Message-ID: <201207092002243437160@gmail.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Dave Chinner , Neil Brown Cc: Christoph Hellwig , linux-raid , Ingo J?rgensmann , xfs On 2012-07-02 16:08 Dave Chinner Wrote: >On Mon, Jul 02, 2012 at 04:41:13PM +1000, NeilBrown wrote: >> On Mon, 2 Jul 2012 02:18:27 -0400 Christoph Hellwig wrote: >> >> > Ping to Neil / the raid list. >> >> Thanks for the reminder. >> >> > [snip] > >That's true, but the characterisitics of spinning disks have not >changed in the past 20 years, nor has the typical file size >distributions in filesystems, nor have the RAID5/6 algorithms. So >it's not really clear to me why you;d woul deven consider changing >the default the downsides of large chunk sizes on RAID5/6 volumes is >well known. This may well explain the apparent increase in "XFS has >hung but it's really just waiting for lots of really slow IO on MD" >cases I've seen over the past couple of years. > At present, cat /sys/block/sdb/queue/max_sectors_kb: is 512k. Maybe because this. >The only time I'd ever consider stripe -widths- of more than 512k or >1MB with RAID5/6 is if I knew my workload is almost exclusively >using large files and sequential access with little metadata load, >and there's relatively few workloads where that is the case. >Typically those workloads measure throughput in GB/s and everyone >uses hardware RAID for them because MD simply doesn't scale to this >sort of usage. > >> If 512K is always suboptimal for XFS then that is unfortunate but I don't > >I think 512k chunk sizes are suboptimal for most users, regardless >of the filesystem or workload.... > >> think it is really possible to choose a default that everyone will be happy >> with. Maybe we just need more documentation and warning emitted by various >> tools. Maybe mkfs.xfs could augment the "stripe unit too large" message with >> some text about choosing a smaller chunk size? > >We work to the mantra that XFS should always choose the defaults >that give the best overall performance and aging characteristics so >users don't need to be a storage expert to get the best the >filesystem can offer. The XFS warning is there to indicate that the >user might be doing something wrong. If that's being emitted with a >default MD configuration, then that indicates that the MD defaults >need to be revised.... > >If you know what a stripe unit or chunk size is, then you know how >to deal with the problem. But for the majority of people, that's way >more knowledge than they are prepared to learn about or should be >forced to learn about. > >Cheers, > >Dave. >-- >Dave Chinner >david@fromorbit.com >-- >To unsubscribe from this list: send the line "unsubscribe linux-raid" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs