Poor performance after system recovery

[bobfandango]

I'm running FreeNAS 8.3.0 Release. My system failed to boot and it appears the USB flash drive was bad. I installed a fresh image on a new USB drive, booted, autoimported my zpool and reloaded the system configuration. Everything appears to work correctly *except* performance is noticeably degraded.

System is a N40L, 8 gigs of RAM, 4 x 2TB drives configured as RAIDZ. Previously, file transfers from my Mac over GigE would nearly saturate the connection at about 90 to 100 MB/s. Now, it averages about 45 to 50. Further, a scrub took 8.5 hours instead of what used to be about 3.5 hours. Lastly, a test with dd yields results that, I think, are not in line with what others see.

/mnt/myzfs/iotest# dd if=/dev/zero of=/mnt/myzfs/iotest/ddfile bs=2048k count=10000
20971520000 bytes transferred in 218.945130 secs (95784364 bytes/sec)

/mnt/myzfs/iotest# dd of=/dev/null if=/mnt/myzfs/iotest/ddfile bs=2048k count=10000
20971520000 bytes transferred in 107.265584 secs (195510239 bytes/sec)

I basically have no idea what is causing this. One possible cause, however, is this. The System Information tab in the UI says I have 3503 MB of memory which should not be the case.

In relevant part, dmesg reports as follows:

real memory = 8589934592 (8192 MB)
avail memory = 3600793600 (3433 MB)

Anyone have any idea what is going on with the memory, and is it related to the poor performance?

Thanks...

 

[bobfandango]

This is resolved... Like a dumba**, I installed the x86 image by mistake.

 

[gpsguy]

Did you accidentally install the 32 bit version, instead of the 64 bit one?

With <4Gb of RAM, "ZFS disables pre-fetching (caching)" is disabled.