Date: Thu, 8 Dec 2011 12:24:18 +0100 From: Matthias Apitz <guru@unixarea.de> To: Hans Petter Selasky <hselasky@c2i.net> Cc: freebsd-questions@freebsd.org, freebsd-usb@freebsd.org Subject: Re: restore(8) to UFS on USB key: terrible slow Message-ID: <20111208112418.GA2370@tinyCurrent> In-Reply-To: <201112081147.46641.hselasky@c2i.net> References: <20111208063711.GA6482@tinyCurrent> <201112081010.36695.hselasky@c2i.net> <20111208091943.GA7014@tinyCurrent> <201112081147.46641.hselasky@c2i.net>
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El día Thursday, December 08, 2011 a las 11:47:46AM +0100, Hans Petter Selasky escribió:
> > I know (as I said) that dd(1) per default writes in blocks of 512 bytes;
> > but this is not the problem; the problem is the poor performance of
> > restore(8); the dd(1) was just to see if the USB key performs fast
> > enough in general; please read my post again :-)
>
> Hi,
>
> The "restore" utility also has a -b option for blocksize. Did you try that?
Hi,
I know, but I think this does not make any diff, because at the moment
restore(8) is only creating (empty) dirs and not storing files to the
disk; if one watches the restore(8) with truss(1) it looks like this:
# truss -p 2123
write(1,"Make node ./home/guru/myThings/F"...,80) = 80 (0x50)
lseek(4,0x0,SEEK_CUR) = 4517312 (0x44edc0)
lseek(4,0x44ec98,SEEK_SET) = 4517016 (0x44ec98)
read(4,"7t\^W\0\f\0\^D\^A.\0\0\0(t\^W\0"...,1024) = 1024 (0x400)
lseek(4,0x0,SEEK_CUR) = 4518040 (0x44f098)
mkdir("./home/guru/myThings/FreeBSD/9-CURRENT/src/secure/libexec/sftp-server/.svn",0777)
= 0 (0x0)
write(1,"Make node ./home/guru/myThings/F"...,85) = 85 (0x55)
lseek(4,0x0,SEEK_CUR) = 4518040 (0x44f098)
lseek(4,0x44ece0,SEEK_SET) = 4517088 (0x44ece0)
read(4,"8t\^W\0\f\0\^D\^A.\0\0\0007t\^W"...,1024) = 1024 (0x400)
lseek(4,0x0,SEEK_CUR) = 4518112 (0x44f0e0)
i.e. it goes through the DUMP and makes the directories; and any
mkdir(2) takes seconds!!!
one can even see this with:
# truss -d mkdir /mnt/foo
...
0.012703011 sigprocmask(SIG_SETMASK,0x0,0x0) = 0 (0x0)
9.774846524 mkdir("/mnt/foo",0777) = 0 (0x0)
9.775744404
sigprocmask(SIG_BLOCK,SIGHUP|SIGINT|SIGQUIT|SIGKILL|SIGPIPE|SIGALRM|SIGTERM|SIGURG|SIGSTOP|SIGTSTP|SIGCONT|SIGCHLD|SIGTTIN|SIGTTOU|SIGIO|SIGXCPU|SIGXFSZ|SIGVTALRM|SIGPROF|SIGWINCH|SIGINFO|SIGUSR1|SIGUSR2,0x0)
= 0 (0x0)
it takes so long to do mkdir(2)
until now there are no files below /mnt, only dirs;
matthias
--
Matthias Apitz
t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211
e <guru@unixarea.de> - w http://www.unixarea.de/
UNIX since V7 on PDP-11 | UNIX on mainframe since ESER 1055 (IBM /370)
UNIX on x86 since SVR4.2 UnixWare 2.1.2 | FreeBSD since 2.2.5
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