Viktor Turskyi wrote:
Is there any performance problem with hard links in ZFS?
I have a large storage. There will be near 50000 hard links for every file. Is it ok for ZFS? May be some problems with snapshots(every 30 minutes there will be a snapshot creating)? What about difference in speed while working with 50000 hardlinks or 50000 different files?
ps: It would be very useful if you give me some links about hardlinks low-level
processing.
This message posted from opensolaris.org
On my 2 Ghz opteron w/ 2 mirrored zfs disks:
cyber% cat test.c
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <strings.h>
int
main(int argc, char *argv[])
{
int i;
char *filename;
char buffer[1024];
if (argc != 2) {
fprintf(stderr, "usage: %s filename\n", argv[0]);
exit(1);
}
strcpy(buffer, argv[1]);
filename = buffer + strlen(filename);
for (i = 0; i < 50000; i++) {
sprintf(filename, "_%d\n", i);
if(link("foo", buffer) < 0) {
perror("link:");
exit(1);
}
}
}
cyber% ls
test test.c
cyber% cc -o test test.c
cyber% mkfile 10k foo
cyber% /bin/ptime ./test foo
real 0.976
user 0.039
sys 0.936
cyber% ls | wc
100003 50003 538906
cyber% /bin/ptime rm foo_*
real 1.869
user 0.110
sys 1.757
cyber%
So it takes just under 1 second to create 50,000 hardlinks to a file; it
takes just under 2 seconds to delete 'em w/ rm. It would prob. be
faster to use a program to delete them.
- Bart
--
Bart Smaalders Solaris Kernel Performance
[EMAIL PROTECTED] http://blogs.sun.com/barts
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