ARMHF - snapraid unable to read config file

[Hans Dampf]

Hi,

I want to use snapraid on my turris omnia, thus I cross compiled snapraid for armhf (turris is equiped with a an armv7 running an openwrt fork). The result is runnable snapraid version (at the moment the current beta because I intend to use btrfs without subvolumes).

$ file snapraid
snapraid: ELF 32-bit LSB  executable, ARM, EABI5 version 1 (SYSV), dynamically linked (uses shared libs), not stripped

However, snapraid always fails to start, because it is unable to read the config file (which is correct):

# ./snapraid status
Self test...
Error opening the configuration file '/etc/snapraid.conf'. Invalid argument.

I did some research a found out that snapraid is trying to use a function which is not implemented on 32bit arm called fadvise64_64:

# strace ./snapraid status
execve("./snapraid", ["./snapraid", "status"], [/* 13 vars */]) = 0
set_tls(0xb6fe7b64, 0, 0xb6fe7918, 0, 0xb6fe7a98) = 0
set_tid_address(0xb6fe7ab4)             = 17182
open("/etc/ld-musl-armhf.path", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
open("/lib/libgcc_s.so.1", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
...
clock_gettime(CLOCK_MONOTONIC_RAW, {227984, 541119920}) = 0
open("/etc/snapraid.conf", O_RDONLY|O_LARGEFILE) = 3
fadvise64_64(3, 0, 0, POSIX_FADV_NORMAL) = -1 ENOSYS (Function not implemented)
close(3)                                = 0
writev(2, [{"Error opening the configuration "..., 77}, {NULL, 0}], 2Error opening the configuration file '/etc/snapraid.conf'. Invalid argument.
) = 77
exit_group(1)                           = ?
+++ exited with 1 +++

So is this my fault? Did I do something wrong when compiling snapraid? Or is this a bug? I would be super happy if I can run snapraid on my turris omnia since I more or less bought it to be my NAS.

Thank you for any help!

[Walter Tuppa]

Just look at the man page of fadvise64. There is a ARM section.
If you compile the sources, I think you can just comment this call out as a first try.

[Andrea Mazzoleni]

Hi Hans,

Please try with the beta 71 at http://beta.snapraid.it/

I changed the fadvise calls to ignore the ENOSYS error that seems to be returned in the armhf case.

Ciao,
Andrea

[Hans Dampf]

Awesome Andrea, thank you very much for the quick fix.
Does this function not being available affect the performance of snapraid?

[Andrea Mazzoleni]

Hi Hans,

Difficult to say, but you can obtain the same effect increasing manually the readahead size, like with:

echo 256 > /sys/block/sdX/queue/read_ahead_kb

Where sdX are the disk devices used in your array.

Ciao,
Andrea