# slow hdd write speed



## da1 (Aug 30, 2010)

Hello fellas,

My system is a 8.0-RELEASE i386 with 6 hdd's and 1 S-ATA1 pci controller (SiI 3512).
The system has the following (more or less packages) on it:

```
xfce4
kde
pure-ftpd
bind9
apache
samba
cups
mysql
sqlite
```
the first 4 disks are in 2 raid1 mirror (gm0 and gm1) and the last 2 have their own mountpoints.

up to 5 days ago (wednesday 25th,2010) the disks were operating at ~30->35 MB write speed.

*The Problem*
yesterday (august 29th, 2010) I noticed that a copy process starts at 13 MB (instead of the usual 30MB) and instead of increasing, it fluctuates a lot (+/- 2-3 MB) and it decreases.


I ran some tests:

1) copy (with mc) between disks (from each to each) -> slow disk ~12-13 MB
2) copy from the network - FTP - (1Gb network) to (each of ) the disks -> 10MB write speed
3) copy from the network - SMB - (1Gb network) to (each of ) the disks -> 7 MB write speed
4) dd if=/dev/zero of=5GB bs=500M count=10 (usually gives me 56MB) -> 49MB (inconclusive test)

I couldn't see anything weird in /var/log/messages or in smartctl -A <disk>

One thing that popped into my head was to check for the CPU temp. It was 65 degrees centigrade (faulty cooler). The cooler was replaced and the temp dropped to 40 (confirmed by lmmon, healthd, mbmon, consolehm and fingermeter (the last one is where you out your finger on the radiator )). The mobo temp was 38. again, confirmed by all of the above mentioned apps/method. 

I'm quite out of ideas. Can anyone support me here pls ?


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## graudeejs (Aug 30, 2010)

Check free disk space. If you are running out of free space, things could get slower.
Check if you are swapping.... If you are swapping things will be quite slow


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## da1 (Aug 30, 2010)

ups ... I forgot to mention those "small" details.

gm0 - 31%
gm1 - 7%
hdd1 - 22%
hdd2 - 67%


swap:

```
Device          1K-blocks     Used    Avail Capacity
/dev/mirror/gm0s1b   5242880       96  5242784     0%
```


also, the CPU does not go above 10-20% at my "max" load. So there is enough CPU time to compute.



LE: on wednesday (bloody wednesday), I swapped 1 hdd with another one. The old one was a Seagate pipeline, and the new one is a WD caviar green. After swapping, I did all previous mentioned tests and got 30-38 MB write speed on all the rest of the disks (all are Seagate pipeline) and I got 35-38 on the WD. So, all looked ok.


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