On 07/05/12 20:10, Martin Mokrejs wrote: > Hi Daniel, > > Daniel Pocock wrote: > >> >> Hi, >> >> I'm testing a problem with the following combination: >> - SB700/SB800 type controller in AHCI mode (in a HP Microserver N36L) >> - Seagate Barracuda 1TB 7k2 drive with NCQ >> > Is that a disk with 4k hardware sectors (Advanced Format)? Where does > you partition start? At sector 63 or 2048? ;-) > > At 2048: Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x484d5754 Device Boot Start End Blocks Id System /dev/sdb1 * 2048 499711 248832 83 Linux Partition 1 does not end on cylinder boundary. /dev/sdb2 499712 1953523711 976512000 fd Linux raid autodetect >> I've got a fresh 256MB partition, formatted ext4, mounted >> barrier=1,data=ordered, write-cache enabled (hdparm -W 1 /dev/sdb) and >> shared over NFS. >> >> When the NFS client writes, >> - unpacking a source tarball, many small files, iostat reports speeds >> under 500kBytes/sec >> - dd conv=fsync, iostat reports about 50MB/sec >> >> If I set up a USB disk on the same box, with a partition formatted >> exactly the same way, the iostat reports the write speed (unpacking the >> same tarball) is over 5MBytes/sec - not so fast, but 10 times faster >> than the AHCI device. >> > So USB is at speed 10 times less, right? > > No - the USB is 10x faster, 5MBytes/sec, the SATA disk is giving me barely 500kBytes/sec for the same write over NFS > Martin > -- > To unsubscribe from this list: send the line "unsubscribe linux-ide" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
