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On Thursday 30 September 2010, Adam Carter wrote: |
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> Taring my mp3 collection from 2.5in 500MB internal sata drive (sda) to |
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> esata 3.5in 500MB drive (sdb) and it seems slow. In vmstat i can see that |
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> the external drive writes faster than the internal can read (external has |
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> periods of inactivity) |
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> # time tar cf /mnt/usbdrive/mp3back.tar mp3/ |
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> |
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> real 10m9.679s |
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> user 0m1.577s |
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> sys 2m1.769s |
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> # du -ks mp3/ |
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> 21221661 mp3/ |
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> |
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> So 21221MB in 610 seconds = 35 MB/s |
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> |
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> # hdparm -t /dev/sda |
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> |
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> /dev/sda: |
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> Timing buffered disk reads: 220 MB in 3.01 seconds = 73.14 MB/sec (77 |
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> with --direct) |
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> |
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> FWIW; |
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> # hdparm /dev/sda |
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> |
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> /dev/sda: |
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> multcount = 16 (on) |
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> IO_support = 1 (32-bit) |
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> readonly = 0 (off) |
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> readahead = 256 (on) |
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> geometry = 60801/255/63, sectors = 976773168, start = 0 |
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> |
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> |
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> So the should i expect filesystem (reiser3) and other overhead to cut the |
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> read performance to less than half of what hdparm reports? Anything else i |
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> can look at to speed it up? Im using CFQ io scheduler. |
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|
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as soon as your harddisk seeks you are lucky to be above 5mb/sec. Yes, even |
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with a modern harddrive. Just look up the seek times and do the math. |
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|
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Your harddisk seeks, everything is slow. |