# Disk transfers too slow

## Ginta

I have two hard disks, one is 160 GB Seagate IDE (hda), and another is 300 GB SATA Seagate (sda), and when I run hdparm (and when I do any disk transfer) I have a slow transfer (comparing with other OSes) (with DMA active).

This is hdparm info:

```

/dev/hda:

 multcount    = 16 (on)

 IO_support   =  1 (32-bit)

 unmaskirq    =  1 (on)

 using_dma    =  1 (on)

 keepsettings =  0 (off)

 readonly     =  0 (off)

 readahead    = 256 (on)

 geometry     = 19457/255/63, sectors = 312581808, start = 0

```

```

/dev/sda:

 IO_support   =  0 (default 16-bit)

 readonly     =  0 (off)

 readahead    = 256 (on)

 geometry     = 36481/255/63, sectors = 586072368, start = 0

```

Speed tests are:

```

/dev/hda:

 Timing cached reads:   2720 MB in  2.00 seconds = 1357.20 MB/sec

 Timing buffered disk reads:  136 MB in  3.02 seconds =  45.03 MB/sec

```

```

/dev/sda:

 Timing cached reads:   2588 MB in  2.00 seconds = 1293.92 MB/sec

 Timing buffered disk reads:  180 MB in  3.00 seconds =  59.92 MB/sec

```

Can someone tell me why is this so slow? And, if possible, tell me his values of hdparm -Tt ?

Thank you!

----------

## brims

That's slow? 

```
hdparm -Tt /dev/hda

/dev/hda:

 Timing cached reads:   1560 MB in  2.00 seconds = 781.51 MB/sec

 Timing buffered disk reads:   84 MB in  3.02 seconds =  27.85 MB/sec
```

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## JeliJami

that seems OK, or at least comparable to mine:

```
# hdparm -tT /dev/sda

/dev/sda:

 Timing cached reads:   2596 MB in  2.00 seconds = 1295.61 MB/sec

 Timing buffered disk reads:  186 MB in  3.01 seconds =  61.72 MB/sec

# hdparm -tT /dev/hda

/dev/hda:

 Timing cached reads:   2324 MB in  2.00 seconds = 1161.02 MB/sec

 Timing buffered disk reads:   84 MB in  3.05 seconds =  27.53 MB/sec
```

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## brims

I just don't see how a gigabyte a second is slow. My drives run at around 700 megabytes a second with hdparm and I have no problems.

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## JeliJami

hi brims,

i just posted my numbers to show Ginta that those hdparm test results of his/her are fine

i agree on your comment

 *brims wrote:*   

> I just don't see how a gigabyte a second is slow

 

----------

## Kabuto

Looks fine.  The top number is speed for the interface.  The second is the ~average speed of the drive.  In actuallity depeneding on where the data is it could be slightly faster or slower than that number.  I have seen some Windows benchmarks that can scan the full platter but don't know of any off hand for Linux.

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## Ginta

I wanted to say that if I copy data from one disk to the other, it seems slow comparing with windows for example (I didn't want to compare, but this is what I believed). If this is acceptable I was wrong (I didn't know what is the average in gentoo for hdparm or transfers).

Anyway, thank you all  :Smile: 

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## brims

 *davjel wrote:*   

> hi brims,
> 
> i just posted my numbers to show Ginta that those hdparm test results of his/her are fine
> 
> i agree on your comment
> ...

 

Don't get me wrong I wasn't disagreeing with you, I saw your numbers being about the same as the original posters and that both were higher than mine, and that the speeds Ginta was getting were by no means slow.

----------

## whoracle

/dev/hda:

 Timing cached reads:   2520 MB in  2.00 seconds = 1259.51 MB/sec

 Timing buffered disk reads:   10 MB in  3.23 seconds =   3.10 MB/sec

I believe someone forgot to enable dma last kernelupgrade   :Embarassed: 

----------

## SnEptUne

I have DMA enabled and here's my timings:

```

/dev/hdb:

 Timing cached reads:   584 MB in  2.01 seconds = 290.63 MB/sec

 Timing buffered disk reads:   16 MB in  3.27 seconds =   4.89 MB/sec

```

I would be really happy if I have half the speed of your hard drive >_<

Maybe time to upgrade my harddrive.

----------

## OlegVekhov

So i have DMA 66 hdd succesfully tweaked with hdparm... and timed reads 150 MB, but buffered reads only 2 MB!!

I have some queschions: one is how to enable write caching (after executing hdparm - W1, hdparm -i shows that WC disabled).

second - where to read about linux HDD caching architecture, how to alter read/write buffer and so on...

Thanks

----------

## SnEptUne

 *OlegVekhov wrote:*   

> So i have DMA 66 hdd succesfully tweaked with hdparm... and timed reads 150 MB, but buffered reads only 2 MB!!
> 
> I have some queschions: one is how to enable write caching (after executing hdparm - W1, hdparm -i shows that WC disabled).
> 
> second - where to read about linux HDD caching architecture, how to alter read/write buffer and so on...
> ...

 

If you don't mind data corruption, you can enable write caching from the kernal configuration.

----------

