Copying a large file system (again)
Tino Schwarze
linux-poweredge.lists at tisc.de
Wed Dec 5 10:31:47 CST 2007
On Mon, Dec 03, 2007 at 08:23:44PM +0100, Tino Schwarze wrote:
> > > I need to copy the whole /backup/backuppc directory structure in one
> > > pass so that hardlinks are preserved. Or I'd need some tool
> > > which could
> > > preserve the hardlinks another way.
> >
> > http://backuppc.sourceforge.net/faq/BackupPC.html#other_installation_topics
> >
> > The section on Copying the Pool may help, specifically using
> > BackupPC_tarPCCopy. If that does not work, you may be able to copy the
> > pool over first, then do the hosts one at a time and try to manually run
> > BackupPC_link.
>
> Oh well, that should do the trick. I'll try copying the pool first, then
> use BackupPC_tarPCCopy to get a tar with almost only hardlinks in it,
> pointing to the pool I've already copied.
I successfully copied the pool! :-) It took amost two days. Now I'm
running BackupPC_tarPCCopy and watching the machines... it seems there's
still some glitch, this time with the destination machine (PE1800 with
3x750 GB SATA PERC RAID). I observe the following:
Everything runs fine, both machines have I/O (I watch using vmstat), the
receiving tar tells me about the files it unpacks (mostly hardlinks to
the pool). After some time, the destination machine slows down
considerably, doing almost no I/O any more with 25%-50% I/O wait (it's
got 4 cores, source has only one and a lot of I/O wait). Using netstat I
see that the receive buffer is quite full (about a meg), the source
machine stops sending data and is 100% idle.
Here is some "vmstat 1" output of the destination machine when it's
getting slow:
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 0 3044 17200 2276 1205492 0 0 2 79 2 2 0 0 99 0
1 0 3044 17076 2276 1205456 0 0 20 3392 695 1666 0 0 99 0
0 0 3044 16084 2276 1205456 0 0 8 0 779 1063 0 0 100 0
0 2 3044 15960 2280 1205460 0 0 0 4956 613 1476 0 0 71 28
0 2 3044 15952 2280 1205464 0 0 8 0 275 1070 0 0 50 50
0 2 3044 15952 2280 1205472 0 0 0 9 277 1073 0 0 50 50
0 2 3044 15952 2280 1205472 0 0 0 0 259 1069 0 0 50 50
1 2 3044 15952 2280 1205472 0 0 0 0 271 1067 0 0 50 50
1 0 3044 16084 2284 1205472 0 0 84 1020 440 1433 0 1 87 12
0 2 3044 15836 2288 1205732 0 0 140 8166 812 2166 0 1 75 24
0 2 3044 15828 2288 1205736 0 0 0 0 281 1115 0 0 50 50
1 2 3044 15828 2288 1205736 0 0 0 88 281 1080 0 0 50 50
1 2 3044 15828 2288 1205736 0 0 0 0 257 1059 0 0 50 50
1 2 3044 15828 2288 1205736 0 0 0 0 272 1067 0 0 50 50
1 2 3044 15852 2288 1205736 0 0 0 0 251 1044 0 0 50 50
-> almost no I/O done, something is blocked there. The whole machine is
slow (e.g. calling a man page, pressing tab in the shell).
I see one of the [pdflush] kernel threads in "D" state when this
happens, so I expect this to be a buffering/flushing issue. Any hints
where to look next? Any kernel parameters to tune?
When everything runs smoothly, the vmstat output looks like this:
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 0 3044 16104 3100 1200360 0 0 648 160 571 1595 0 2 98 0
0 0 3044 16736 3096 1199588 0 0 580 594 567 1663 0 1 99 0
1 0 3044 16232 3096 1199956 0 0 480 539 499 1284 0 1 99 0
1 0 3044 15736 3104 1200480 0 0 500 168 480 1377 0 1 98 0
1 0 3044 16736 3104 1199484 0 0 580 512 585 1566 0 1 98 0
0 0 3044 16124 3104 1200144 0 0 636 192 597 1562 0 1 99 0
1 0 3044 15380 3104 1200880 0 0 684 160 522 1537 0 1 99 0
0 0 3044 16676 3104 1199996 0 0 488 925 631 1840 1 1 98 0
0 0 3044 15920 3112 1200540 0 0 580 220 518 1314 0 2 98 0
3 0 3044 15292 3112 1201188 0 0 676 192 561 1416 0 1 98 0
1 0 3044 16308 3112 1200452 0 0 612 561 542 1510 0 1 99 0
1 0 3044 15952 3112 1201148 0 0 680 128 519 1483 0 1 99 0
1 0 3044 16508 3104 1200236 0 0 588 689 606 1533 0 1 98 0
1 0 3044 16012 3112 1200920 0 0 620 200 561 1482 0 1 99 0
2 0 3044 15780 3112 1201472 0 0 636 224 575 1529 0 1 98 0
0 0 3044 16780 3112 1200512 0 0 616 676 626 1493 0 1 99 0
0 0 3044 16036 3112 1201248 0 0 620 192 559 1375 0 1 99 0
1 0 3044 16788 3112 1200252 0 0 352 3676 1408 4178 1 3 96 0
2 0 3044 16672 3112 1200804 0 0 244 3424 2099 5468 1 4 95 0
1 0 3044 16548 3120 1201452 0 0 560 488 799 2012 0 2 97 0
0 0 3044 15928 3120 1201824 0 0 428 480 489 2220 0 1 98 0
1 0 3044 15432 3120 1202588 0 0 668 288 566 1977 0 1 99 0
1 0 3044 16248 3116 1201672 0 0 612 1185 604 1942 0 2 98 0
1 0 3044 15380 3116 1202376 0 0 632 192 987 1545 0 2 98 0
1 0 3044 16128 3124 1201452 0 0 260 5061 2788 9731 2 5 93 0
0 0 3044 16120 3124 1201816 0 0 128 3648 2655 12920 1 3 96 0
0 0 3044 16120 3124 1202204 0 0 116 2400 1816 7882 1 3 97 0
2 0 3044 15500 3124 1202616 0 0 412 1111 967 3616 0 2 98 0
1 0 3044 16636 3120 1201704 0 0 140 5969 3263 14974 1 6 93 0
2 0 3044 16016 3128 1201900 0 0 80 3656 2573 11685 2 4 94 0
1 0 3044 15892 3128 1202320 0 0 304 128 395 1565 0 1 99 0
Thanks,
Tino.
--
www.craniosacralzentrum.de
www.lebensraum11.de
www.spiritualdesign-chemnitz.de
Tino Schwarze * Parkstraße 17h * 09120 Chemnitz
More information about the Linux-PowerEdge
mailing list