"Simon Baxter" linuxtv@nzbaxters.com writes:
Anyway, I've bought 3x 1.5 TB SATA disks which I'd like to put into a software (mdadm) raid 5 array.
[...]
But does anyone have any production VDR experience with mdadm - good or bad?
If you like good performance and simple recovery, then do not use RAID5. Use RAID1 instead.
I use RAID5 only because I am too lazy to buy some new and larger disks for my VDR at the moment :-)
I have had serious performance-problems with parallel recordings and some Linux-background-jobs (like system-backup). I solved it by raising the I/O-priority of vdr with ionice:
ionice -c2 -n0 vdr -w 120 -v $VIDEODIR -d -t /dev/tty5 -g /tmp ...
Stephan.
But does anyone have any production VDR experience with mdadm - good or bad?
I've now tested and implemented RAID5 on my system. The biggest CPU hit is still with the OSD or noad processes - below is a bunch of tests I ran and the top processes during the test:
1 recording to raid, watching another live top - 07:52:18 up 1 day, 20:29, 3 users, load average: 0.66, 0.54, 0.42 Tasks: 168 total, 2 running, 156 sleeping, 10 stopped, 0 zombie Cpu(s): 20.2%us, 6.7%sy, 0.5%ni, 68.3%id, 1.5%wa, 0.5%hi, 2.4%si, 0.0%st Mem: 2059352k total, 2038636k used, 20716k free, 19724k buffers Swap: 1903692k total, 292k used, 1903400k free, 1412672k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2372 vdruser 20 0 542m 37m 18m S 37.1 1.9 1:09.50 xine 2330 vdruser 20 0 486m 26m 4616 S 10.6 1.3 0:21.68 vdr 3020 root 20 0 369m 24m 18m R 9.6 1.2 157:51.36 Xorg 3521 vdruser 20 0 923m 306m 25m S 1.0 15.3 50:59.10 mms 3723 root 15 -5 0 0 0 S 0.7 0.0 10:12.08 md0_raid5 2455 root 20 0 14880 1188 872 R 0.3 0.1 0:00.32 top 2593 root 15 -5 0 0 0 S 0.3 0.0 1:04.10 kdvb-ca-1:0 3168 vdruser 20 0 139m 5468 3984 S 0.3 0.3 6:03.34 fluxbox
2 recording to raid, watching another live top - 07:55:09 up 1 day, 20:32, 3 users, load average: 1.67, 1.00, 0.61 Tasks: 168 total, 1 running, 157 sleeping, 10 stopped, 0 zombie Cpu(s): 21.8%us, 7.8%sy, 0.3%ni, 66.6%id, 0.7%wa, 0.7%hi, 2.1%si, 0.0%st Mem: 2059352k total, 2038888k used, 20464k free, 20732k buffers Swap: 1903692k total, 292k used, 1903400k free, 1406060k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2372 vdruser 20 0 542m 37m 18m S 39.4 1.9 2:17.04 xine 2330 vdruser 20 0 511m 32m 4616 S 13.9 1.6 0:45.66 vdr 3020 root 20 0 369m 24m 18m S 9.9 1.2 158:08.39 Xorg 3723 root 15 -5 0 0 0 S 1.3 0.0 10:14.20 md0_raid5 3521 vdruser 20 0 923m 306m 25m S 1.0 15.3 51:00.61 mms 2455 root 20 0 14880 1188 872 R 0.7 0.1 0:01.19 top 271 root 20 0 0 0 0 S 0.3 0.0 0:09.16 pdflush
3 recording to raid, watching another live top - 07:55:52 up 1 day, 20:32, 3 users, load average: 1.69, 1.08, 0.65 Tasks: 168 total, 1 running, 157 sleeping, 10 stopped, 0 zombie Cpu(s): 22.1%us, 7.2%sy, 0.5%ni, 68.1%id, 0.0%wa, 0.0%hi, 2.1%si, 0.0%st Mem: 2059352k total, 2040896k used, 18456k free, 20964k buffers Swap: 1903692k total, 292k used, 1903400k free, 1401876k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2372 vdruser 20 0 606m 37m 18m S 34.2 1.9 2:32.21 xine 2330 vdruser 20 0 536m 37m 4616 S 14.3 1.9 0:51.80 vdr 3020 root 20 0 369m 24m 18m S 9.6 1.2 158:12.50 Xorg 3723 root 15 -5 0 0 0 S 1.7 0.0 10:14.83 md0_raid5 2455 root 20 0 14880 1188 872 R 0.7 0.1 0:01.41 top 3168 vdruser 20 0 139m 5468 3984 S 0.7 0.3 6:04.13 fluxbox 3521 vdruser 20 0 923m 306m 25m S 0.7 15.3 51:00.98 mms
4 recording to raid, watching another live top - 07:56:37 up 1 day, 20:33, 3 users, load average: 1.89, 1.19, 0.71 Tasks: 168 total, 2 running, 156 sleeping, 10 stopped, 0 zombie Cpu(s): 23.6%us, 8.0%sy, 0.3%ni, 66.3%id, 0.0%wa, 0.3%hi, 1.5%si, 0.0%st Mem: 2059352k total, 2042836k used, 16516k free, 21264k buffers Swap: 1903692k total, 292k used, 1903400k free, 1393688k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2372 vdruser 20 0 606m 38m 18m S 36.8 1.9 2:48.28 xine 2330 vdruser 20 0 583m 44m 4616 S 15.6 2.2 0:58.77 vdr 3020 root 20 0 369m 24m 18m S 9.0 1.2 158:16.78 Xorg 3723 root 15 -5 0 0 0 S 2.3 0.0 10:15.70 md0_raid5 3521 vdruser 20 0 923m 306m 25m S 1.0 15.3 51:01.39 mms 3168 vdruser 20 0 139m 5468 3984 S 0.7 0.3 6:04.30 fluxbox 2455 root 20 0 14880 1188 872 R 0.3 0.1 0:01.64 top 2593 root 15 -5 0 0 0 S 0.3 0.0 1:04.21 kdvb-ca-1:0 1 root 20 0 4080 852 604 S 0.0 0.0 0:00.50 init
4 recording to raid, watching another live, OSD up top - 07:57:19 up 1 day, 20:34, 3 users, load average: 1.87, 1.28, 0.75 Tasks: 168 total, 1 running, 157 sleeping, 10 stopped, 0 zombie Cpu(s): 32.6%us, 7.6%sy, 0.5%ni, 55.4%id, 1.1%wa, 0.2%hi, 2.6%si, 0.0%st Mem: 2059352k total, 2033996k used, 25356k free, 21516k buffers Swap: 1903692k total, 292k used, 1903400k free, 1383424k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2372 vdruser 20 0 603m 36m 15m S 57.9 1.8 3:05.55 xine 2330 vdruser 20 0 583m 45m 4616 S 12.9 2.2 1:05.39 vdr 3020 root 20 0 366m 20m 14m S 8.9 1.0 158:20.76 Xorg 3723 root 15 -5 0 0 0 S 2.3 0.0 10:16.61 md0_raid5 3521 vdruser 20 0 923m 306m 25m S 1.0 15.3 51:01.77 mms 2455 root 20 0 14880 1188 872 R 0.7 0.1 0:01.86 top 7 root 15 -5 0 0 0 S 0.3 0.0 0:02.62 ksoftirqd/1
4 recording to raid, watching recording top - 07:58:23 up 1 day, 20:35, 3 users, load average: 1.69, 1.36, 0.82 Tasks: 168 total, 2 running, 156 sleeping, 10 stopped, 0 zombie Cpu(s): 17.4%us, 6.0%sy, 0.2%ni, 74.4%id, 0.2%wa, 0.5%hi, 1.3%si, 0.0%st Mem: 2059352k total, 2042588k used, 16764k free, 21944k buffers Swap: 1903692k total, 292k used, 1903400k free, 1390068k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2372 vdruser 20 0 603m 37m 15m S 27.9 1.9 3:37.25 xine 2330 vdruser 20 0 593m 45m 4640 S 11.3 2.2 1:15.44 vdr 3020 root 20 0 366m 20m 13m S 9.6 1.0 158:26.70 Xorg 3723 root 15 -5 0 0 0 S 2.3 0.0 10:17.98 md0_raid5 3521 vdruser 20 0 923m 306m 25m S 1.0 15.3 51:02.34 mms 2455 root 20 0 14880 1188 872 R 0.7 0.1 0:02.18 top 616 root 15 -5 0 0 0 S 0.3 0.0 0:07.85 kjournald 2291 mysql 20 0 183m 22m 3364 S 0.3 1.1 3:04.75 mysqld
4 recording to raid, watching recording, OSD up top - 07:58:50 up 1 day, 20:35, 3 users, load average: 1.45, 1.33, 0.82 Tasks: 168 total, 1 running, 157 sleeping, 10 stopped, 0 zombie Cpu(s): 32.4%us, 6.7%sy, 0.5%ni, 56.8%id, 0.2%wa, 0.8%hi, 2.6%si, 0.0%st Mem: 2059352k total, 2034396k used, 24956k free, 22144k buffers Swap: 1903692k total, 292k used, 1903400k free, 1381876k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2372 vdruser 20 0 603m 37m 15m S 62.3 1.9 3:47.77 xine 2330 vdruser 20 0 593m 45m 4640 S 12.9 2.2 1:18.94 vdr 3020 root 20 0 366m 20m 13m S 9.0 1.0 158:28.88 Xorg 3723 root 15 -5 0 0 0 S 2.3 0.0 10:18.57 md0_raid5 3521 vdruser 20 0 923m 306m 25m S 1.0 15.3 51:02.59 mms 2455 root 20 0 14880 1188 872 R 0.7 0.1 0:02.32 top 2291 mysql 20 0 183m 22m 3364 S 0.3 1.1 3:04.79 mysqld
7 recording to raid, watching recording, OSD up top - 08:09:15 up 1 day, 20:46, 3 users, load average: 1.88, 1.30, 0.96 Tasks: 168 total, 1 running, 157 sleeping, 10 stopped, 0 zombie Cpu0 : 37.2%us, 6.9%sy, 0.3%ni, 50.3%id, 0.3%wa, 0.3%hi, 4.6%si, 0.0%st Cpu1 : 29.2%us, 9.6%sy, 0.3%ni, 57.1%id, 1.3%wa, 1.3%hi, 1.3%si, 0.0%st Mem: 2059352k total, 2034760k used, 24592k free, 13844k buffers Swap: 1903692k total, 292k used, 1903400k free, 1368568k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2372 vdruser 20 0 603m 38m 15m S 60.7 1.9 7:18.46 xine 2330 vdruser 20 0 641m 66m 4660 S 17.2 3.3 2:28.49 vdr 3020 root 20 0 366m 20m 14m S 8.3 1.0 159:19.67 Xorg 3723 root 15 -5 0 0 0 S 3.3 0.0 10:25.22 md0_raid5 2580 root 20 0 14880 1192 876 R 0.7 0.1 0:01.28 top 3168 vdruser 20 0 139m 5468 3984 S 0.7 0.3 6:06.98 fluxbox 3521 vdruser 20 0 923m 306m 25m S 0.7 15.3 51:07.72 mms 83 root 15 -5 0 0 0 S 0.3 0.0 0:02.32 kblockd/0 2455 root 20 0 14880 1192 872 S 0.3 0.1 0:05.32 top 2593 root 15 -5 0 0 0 S 0.3 0.0 1:04.52 kdvb-ca-1:0 7566 root 15 -5 0 0 0 S 0.3 0.0 0:00.71 kjournald 1 root 20 0 4080 852 604 S 0.0 0.0 0:00.50 init
Mutliple parallel noad tasks: top - 08:10:54 up 1 day, 20:47, 3 users, load average: 2.35, 1.48, 1.05 Tasks: 173 total, 7 running, 156 sleeping, 10 stopped, 0 zombie Cpu0 : 7.6%us, 4.3%sy, 85.7%ni, 0.0%id, 0.0%wa, 0.3%hi, 2.0%si, 0.0%st Cpu1 : 7.3%us, 6.0%sy, 86.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.7%si, 0.0%st Mem: 2059352k total, 2043880k used, 15472k free, 14420k buffers Swap: 1903692k total, 292k used, 1903400k free, 1384748k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2648 vdruser 39 19 131m 3820 804 R 35.9 0.2 0:02.22 noad 2642 vdruser 39 19 131m 4460 808 R 35.6 0.2 0:03.75 noad 2638 vdruser 39 19 131m 3928 840 R 28.6 0.2 0:05.08 noad 2650 vdruser 39 19 131m 3804 804 R 26.3 0.2 0:01.31 noad 2646 vdruser 39 19 131m 4564 816 R 25.6 0.2 0:01.86 noad 2644 vdruser 39 19 132m 4852 816 R 24.3 0.2 0:02.32 noad 2372 vdruser 20 0 603m 38m 15m S 14.0 1.9 7:54.20 xine 3020 root 20 0 366m 20m 14m S 4.7 1.0 159:27.91 Xorg 2330 vdruser 20 0 501m 40m 4660 S 3.0 2.0 2:44.70 vdr 3521 vdruser 20 0 923m 306m 25m S 0.7 15.3 51:08.62 mms 83 root 15 -5 0 0 0 S 0.3 0.0 0:02.34 kblockd/0 271 root 20 0 0 0 0 S 0.3 0.0 0:09.29 pdflush 273 root 15 -5 0 0 0 S 0.3 0.0 0:09.87 kswapd0 864 root 15 -5 0 0 0 S 0.3 0.0 0:38.77 scsi_eh_4 2580 root 20 0 14880 1196 876 R 0.3 0.1 0:01.76 top 2593 root 15 -5 0 0 0 S 0.3 0.0 1:04.56 kdvb-ca-1:0 1 root 20 0 4080 852 604 S 0.0 0.0 0:00.50 init
top - 08:00:26 up 1 day, 20:37, 3 users, load average: 1.35, 1.24, 0.83 Tasks: 170 total, 4 running, 156 sleeping, 10 stopped, 0 zombie Cpu(s): 6.8%us, 3.7%sy, 87.7%ni, 0.0%id, 0.0%wa, 0.3%hi, 1.5%si, 0.0%st Mem: 2059352k total, 2043444k used, 15908k free, 22720k buffers Swap: 1903692k total, 292k used, 1903400k free, 1403140k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2527 vdruser 39 19 132m 4968 816 R 53.9 0.2 0:01.87 noad 2525 vdruser 39 19 131m 4516 804 R 51.2 0.2 0:02.29 noad 2521 vdruser 39 19 131m 4424 804 R 42.9 0.2 0:03.92 noad 2372 vdruser 20 0 603m 37m 15m S 15.0 1.9 4:31.98 xine 3020 root 20 0 366m 20m 13m S 4.3 1.0 158:37.08 Xorg 2330 vdruser 20 0 483m 24m 4652 S 2.7 1.2 1:30.75 vdr 84 root 15 -5 0 0 0 S 0.3 0.0 0:12.46 kblockd/1 273 root 15 -5 0 0 0 S 0.3 0.0 0:09.64 kswapd0 2455 root 20 0 14880 1192 872 R 0.3 0.1 0:02.80 top 3521 vdruser 20 0 923m 306m 25m S 0.3 15.3 51:03.47 mms
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Simon Baxter -
Stephan Loescher