30 replies to this topic

[Robinson]

I have an 640 GB ADATA SH02 USB hard drive, which is recognized as SAMSUNG(HM641JX). It is connected to my ET9000 with 2 USB cables.

Unfortunately, I have recently observed that writing to disk is terribly slow, so recording satellite TV does not make sense because of the stutter when playing the video.

Reading speed seems to be OK.

I have initialized it in my box but this does not seem to have helped.

Is there a way to diagnoze it further uwing USB?

Opening the case does not reveal any SATA connection.

What is the best way to test it either in ET9000 or in a Windows machine (in this case, EXT would need to be changed to NTFS?).

Thanks.

[WanWizard]

How slow is slow? Can you do this?

hdparm -Tt /dev/sda

(if your usb disk isn't sda, replace it my the device name of your disk)

 

And why connected with TWO cables? Doesn't the box gets confused when it sees the same device twice?

[Robinson]

root@et9x00:~# hdparm -Tt /dev/sda

/dev/sda:
Timing buffer-cache reads:   232 MB in 0.50 seconds = 465915 kB/s
Timing buffered disk reads:   70 MB in 3.00 seconds = 23830 kB/s

 

 

I am using the sort of cable atatched.

Anyway, the problem started when only one was connected so I thought there was not enough power and I connected the other but the problem is still there.

Attached Files

•  usb-y-cable.gif   12.33KB   6 downloads

[MiLo]

Try an external power supply. The box will supply only 2,5W, even when using multiple connectors (they all just go to the same internal USB hub anyway).

[MiLo]

Or just take the disk out of the enclosure (USB disks don't really exist) and put it into the box using SATA, that will give much better performance.

[WanWizard]

Ok, so read speed is more than sufficient.
 
You can test write using

dd if=/dev/zero of=/media/usb/testfile bs=8k count=10k; rm -f /media/usb/testfile

(if your disk is mounted elsewhere, change the filename accordingly)

[Robinson]

I did bu there is no SATA connection there. Unfortunately.

 

 

root@et9x00:~# dd if=/dev/zero of=/media/usb/testfile bs=8k count=10k; rm -f /me
dia/usb/testfile
10240+0 records in
10240+0 records out
83886080 bytes (80.0MB) copied, 1.066289 seconds, 75.0MB/s

 

Maybe it looks OK now but for how long?

Edited by Robinson, 7 November 2015 - 14:19.

[MiLo]

I did bu there is no SATA connection there. Unfortunately.

 

Where is "there"? The 9000 has internal SATA. Is it an IDE disk then? There are converters for that too...

[WanWizard]

The SAMSUNG HM641JX is a disk especially manufactured for USB enclosures, it has a USB connection directly on the PCB, so no USB-to-SATA needed like used in some solutions.

The WD Passport USB disks are the same...

[Robinson]

 

I did bu there is no SATA connection there. Unfortunately.

 

Where is "there"? The 9000 has internal SATA. Is it an IDE disk then? There are converters for that too...

 

As WanWizard already pointed out, there is no SATA in the disk after removing the case, so it is not possible to use it as SATA.

[Robinson]

root@et9x00:~# dd if=/dev/zero of=/media/usb/testfile bs=8k count=10k; rm -f /me

dia/usb/testfile
10240+0 records in
10240+0 records out
83886080 bytes (80.0MB) copied, 1.066289 seconds, 75.0MB/s

 

Maybe it looks OK now but for how long?

 

Any chance to make a more in-depth test for this USB disk?

How to make a longer test like this?

Or should I rather connect it to a PC and make some tests using Windows, which I think would require re-formatting it?

[WanWizard]

A write speed of 75MB/s is more than enough to handle a handful of simultaneous recordings, even if they're all HD, and it's roughly half the speed of an internal SATA disk.

 

So I wonder what you're problem exactly is...

[Robinson]

Apparently the problem is not there all the time.

I have just made a 20-second recording of an 18 mbit/s channel and the recording seems to be OK. So the problem is temporarily(?) gone.

[Robinson]

Look at the result now, please:

root@et9x00:~# dd if=/dev/zero of=/media/hdd/testfile bs=8k count=10k; rm -f /me
10240+0 records in
10240+0 records out
83886080 bytes (80.0MB) copied, 448.196632 seconds, 182.8KB/s

My problem regarding WRITE SPEED was gone for a while only and now it is back.

 

 

By the way, when buying a 2.5" HDD, should I also take into account cache size and RPM or aren't these 2 parameters so important in ET9000?

[betacentauri]

From my point of view cache size and rpm are not important. You can buy a hdd with low rpm. I have a 3.5" hdd with 5400 rpm. All current hdd should be fast enough to record 4 and more recordings at the same time.
Try to write bigger chunks (1 MB or so) with dd. If it's still slow please check with smartmontools (smartctl) the smart values.

[Jan Gruuthuse]

Backup/copy all important files from the USB HDD. And format the SAMSUNG(HM641JX) on the ET9000. Most likely this should improve the situation.

If you have used the hard disc for some years, consider the possibility of mechanical / magnetic wear and tear.

[MiLo]

A write speed of 182kB/s is not just a slow disk (even my first 10MHz PC-XT could write faster than that), that's just broken.

[Robinson]

First I will try to use an external power supply with this disk. I didn't have a chance to do it yet.

[Robinson]

Backup/copy all important files from the USB HDD. And format the SAMSUNG(HM641JX) on the ET9000. Most likely this should improve the situation.

I already did that several weeks ago. It seemed to imrove the situation for some time but the problem returned.

[Robinson]

From my point of view cache size and rpm are not important. You can buy a hdd with low rpm. I have a 3.5" hdd with 5400 rpm. All current hdd should be fast enough to record 4 and more recordings at the same time.
Try to write bigger chunks (1 MB or so) with dd. If it's still slow please check with smartmontools (smartctl) the smart values.

 

Does it work with USB disks?

root@et9x00:~# smartctl -a /dev/sda
smartctl 5.42 2011-10-20 r3458 [mips-linux-3.8.7] (local build)
Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net

/dev/sda: Unknown USB bridge [0x125f:0xa02a (0x000)]
Smartctl: please specify device type with the -d option.