Re: Few questions
Guy Watkins wrote: > man md > man mdadm and http://linux-raid.osdl.org/index.php/Main_Page :) - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
/proc/mdstat docs (was Re: Few questions)
Michael Makuch wrote: > So my questions are: ... > - Is this a.o.k for a raid5 array? So I realised that /proc/mdstat isn't documented too well anywhere... http://linux-raid.osdl.org/index.php/Mdstat Comments welcome... David - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: /proc/mdstat docs (was Re: Few questions)
many thanks . david. It is very useful. On 12/8/07, David Greaves <[EMAIL PROTECTED]> wrote: > Michael Makuch wrote: > > So my questions are: > ... > > - Is this a.o.k for a raid5 array? > > So I realised that /proc/mdstat isn't documented too well anywhere... > > http://linux-raid.osdl.org/index.php/Mdstat > > Comments welcome... > > David > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Raz - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: mounting raid5 with different unit values
Well... this thing actually works just fine with a newer kernel ( 2.6.18-8-el5 centos5 ). I managed to mount / mkfs.xfs over raid5 with a pseudo raid5 unit size, and with the appropriate raid 5 patches and user space access-pattern, I elimintaed in 99% cases the read penalty . I sincerly hope I won't be getting any crashes with this file system tunnings. so ... first, chris and all you xfs guys, many many thanks. Chris, How "dangerous" these tunnings are ? Am I to expect "weird" behaviour of the file system ? On 10/8/07, Chris Wedgwood <[EMAIL PROTECTED]> wrote: > On Sun, Oct 07, 2007 at 11:48:14AM -0400, Justin Piszcz wrote: > > > man mount :) > > Ah of course. > > But those will be more restrictive that what you can specify when you > make the file-system (because mkfs.xfs can aligned the AGs to suit). > -- Raz - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Reading takes 100% precedence over writes for mdadm+raid5?
This is what dstat shows me copying lots of large files about (ext3), one file at a time. I've benchmarked the raid itself around 65-70 MB/s maximum actual write I/O so this 3-4MB/s stuff is pretty bad. I should note that ALL other I/O suffers horribly, even on other filesystems. What might the cause be? I should note: going larger in stripe_cache_size (384 and 512) performance stays the same, going smaller (128) performance *increases* and stays more steady to 10-13 MB/s. total-cpu-usage --dsk/sda-- --dsk/sdb-- --dsk/sdc-- --dsk/sdd-- -dsk/total-> usr sys idl wai hiq siq| read writ: read writ: read writ: read writ: read writ> 1 1 95 3 0 0| 12k 4261B: 106k 125k: 83k 110k: 83k 110k: 283k 348k> 0 5 0 91 1 2| 0 0 :2384k 4744k:2612k 4412k:2336k 4804k:7332k 14M> 0 4 0 91 1 3| 0 0 :2352k 4964k:2392k 4812k:2620k 4764k:7364k 14M> 0 4 0 92 1 3| 0 0 :1068k 3524k:1336k 3184k:1360k 2912k:3764k 9620k> 0 4 0 92 1 2| 0 0 :2304k 2612k:2128k 2484k:2332k 3028k:6764k 8124k> 0 4 0 92 1 2| 0 0 :1584k 3428k:1252k 3992k:1592k 3416k:4428k 11M> 0 3 0 93 0 2| 0 0 :1400k 2364k:1424k 2700k:1584k 2592k:4408k 7656k> 0 4 0 93 1 2| 0 0 :1764k 3084k:1820k 2972k:1796k 2396k:5380k 8452k> 0 4 0 92 2 3| 0 0 :1984k 3736k:1772k 4024k:1792k 4524k:5548k 12M> 0 4 0 93 1 2| 0 0 :1852k 3860k:1840k 3408k:1696k 3648k:5388k 11M> 0 4 0 93 0 2| 0 0 :1328k 2500k:1640k 2348k:1672k 2128k:4640k 6976k> 0 4 0 92 0 4| 0 0 :1624k 3944k:2080k 3432k:1760k 3704k:5464k 11M> 0 1 0 97 1 2| 0 0 :1480k 1340k: 976k 1564k:1268k 1488k:3724k 4392k> 0 4 0 92 1 2| 0 0 :1320k 2676k:1608k 2548k: 968k 2572k:3896k 7796k> 0 2 0 96 1 1| 0 0 :1856k 1808k:1752k 1988k:1752k 1600k:5360k 5396k> 0 4 0 92 2 1| 0 0 :1360k 2560k:1240k 2788k:1580k 2940k:4180k 8288k> 0 2 0 97 1 2| 0 0 :1928k 1456k:1628k 2080k:1488k 2308k:5044k 5844k> 1 3 0 94 2 2| 0 0 :1432k 2156k:1320k 1840k: 936k 1072k:3688k 5068k> 0 3 0 93 2 2| 0 0 :1760k 2164k:1440k 2384k:1276k 2972k:4476k 7520k> 0 3 0 95 1 2| 0 0 :1088k 1064k: 896k 1424k:1152k 992k:3136k 3480k> 0 0 0 96 0 2| 0 0 : 976k 888k: 632k 1120k:1016k 968k:2624k 2976k> 0 2 0 94 1 2| 0 0 :1120k 1864k: 964k 1776k:1060k 1856k:3144k 5496k> -- Jon - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: /proc/mdstat docs (was Re: Few questions)
David Greaves wrote: Michael Makuch wrote: So my questions are: ... - Is this a.o.k for a raid5 array? So I realised that /proc/mdstat isn't documented too well anywhere... http://linux-raid.osdl.org/index.php/Mdstat Comments welcome... David One thing, in the section "md device line" you describe how to identify spare devices, but you didn't mention the "(S)" which appears after a spare device, at least it does on mine: # uname -a Linux pecan.makuch.org 2.6.23.1-21.fc7 #1 SMP Thu Nov 1 21:09:24 EDT 2007 i686 i686 i386 GNU/Linux # cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 etherd/e0.0[0] etherd/e0.2[9](S) etherd/e0.9[8] etherd/e0.8[7] etherd/e0.7[6] etherd/e0.6[5] etherd/e0.5[4] etherd/e0.4[3] etherd/e0.3[2] etherd/e0.1[1] 3907091968 blocks level 5, 64k chunk, algorithm 2 [9/9] [U] [==>..] resync = 91.0% (444527040/488386496) finish=560.9min speed=1301K/sec unused devices: Unless that means something else??? But e0.2 is my spare so I'm just assuming "(S)" means spare! Thanks Mike - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Few questions
Guy Watkins wrote: man md man mdadm I use RAID6. Happy with it so far, but haven't had a disk failure yet. RAID5 sucks because if you have 1 failed disk and 1 bad block on any other disk, you are hosed. Hope that helps. I can't believe I've been using a raid array for 2 years and didn't know 'man md' was there. I've lived and breathed off of Software-RAID-HOWTO.html but it never mentions it. Just a suggestion to whom it may concern: it might be nice to mention 'man md' in the Howto as well as the wiki pages. Thanks Mike - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
