I am having some difficulty with fio using /dev/rdsk devices under Solaris. My best guess at this point is that fio is doing something incorrect when it attempts to determine the size of a /dev/rdsk device. Everything works if I use /dev/rdsk/c0t5SOMEDISKd0p0, but if I create a partition which is not as large as the complete disk, when I point fio at the /dev/rdsk device (e.g. /dev/rdsk/c0t5SOMEDISKd0p1), fio promptly bombs out. If I point fio at the /dev/dsk device (e.g. /dev/dsk/c0t5SOMEDISKd0p1), fio works, though I typically get half to a third of the performance using the /dev/dsk devices. I have tested using the "dd" utility, and validated that "dd" will use the /dev/rdsk devices and access only part of the drive without a problem. I am testing on solaris 11 x86, and I have tested fio versions 1.54 and 1.99. Both versions of fio failed the same way. Here's what fio looks like when it bombs out: rand-read: (g=0): rw=randrw, bs=32K-32K/32K-32K, ioengine=solarisaio, iodepth=8 ... rand-read: (g=0): rw=randrw, bs=32K-32K/32K-32K, ioengine=solarisaio, iodepth=8 fio 1.54 Starting 4 processes fio: io_u error on file /dev/rdsk/c0t500151795968D5ABd0p1: I/O error read offset=134944555008, buflen=32768 fio: io_u error on file /dev/rdsk/c0t500151795968D5ABd0p1: I/O error write offset=134455656448, buflen=32768 fio: pid=1382, err=5/file:io_u.c:1197, func=io_u error, error=I/O error fio: io_u error on file /dev/rdsk/c0t500151795968D5ABd0p1: I/O error read offset=156234678272, buflen=32768 fio: pid=1383, err=5/file:io_u.c:1197, func=io_u error, error=I/O error fio: io_u error on file /dev/rdsk/c0t500151795968D5ABd0p1: I/O error read offset=131076620288, buflen=32768 fio: io_u error on file /dev/rdsk/c0t500151795968D5ABd0p1: I/O error write offset=155262877696, buflen=32768 fio: pid=1384, err=5/file:io_u.c:1197, func=io_u error, error=I/O error fio: io_u error on file /dev/rdsk/c0t500151795968D5ABd0p1: I/O error read offset=156624125952, buflen=32768 fio: pid=1385, err=5/file:io_u.c:1197, func=io_u error, error=I/O error Here is my fio config file: [global] bs=32k ioengine=solarisaio iodepth=8 openfiles=1024 runtime=60 ramp_time=10 filename=/dev/rdsk/c0t500151795968D5ABd0p1 [rand-read] rw=randrw numjobs=4 rwmixwrite=20 norandommap=1 file_service_type=random group_reporting What additional information, if any should I provide? Cheers Ross -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html