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Adam D

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Determine hardware problem - extremely slow write speed

Computer specs:

Operating System
  Windows Small Business Server 2011 Standard 64-bit SP1
CPU
  Intel Core i7 4770K @ 3.50GHz      48 °C
  Haswell 22nm Technology
RAM
  16.0GB Dual-Channel DDR3 @ 800MHz (11-11-11-29)
Motherboard
  MSI Z87-G41 PC Mate(MS-7850) (SOCKET 0)      36 °C
Graphics
  Intel HD Graphics 4600 (MSI)
Storage
  Hard Drives (3): Toshiba DT01ACA200 (2 TB drives)
Optical Drives
  HL-DT-ST DVDRAM GH24NSB0 SCSI CdRom Device

==================================
The Setup:

RAID 5 - two partitions/volumes
SBS 2011 with Exchange 2010 - 10 mailboxes
Currently up-to-date

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The problem:

Windows works, however; transfer rates are a max of 4 MB / sec.  When running "Hard Disk Sentinel" the "short test" which should only take a minute took 21 minutes last night on Disk #0 (did not have a chance to run the test on #1 and #2).  However; this morning it took 1:15 min and the other two took 1:05 min.

A previous RAM test using Memtest86 came back clean - will be running it again this weekend.

A read test using "HD_speed.exe" showed no problem.

When attempting to transfer a file from C: to D: (same drives just different volumes) a 1.2GB file was estimated to take 5 hours.  When transferring a file over the network the same problem occurred and it showed a transfer rate of 2 MB / sec.

It is not fully consistent and I don't know if this is a hardware (most likely) or a software (Windows OS) issue.

What I need to know is how I can figure the problem out and solve it.

Thanks.
Avatar of Don Thomson
Don Thomson
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Have you done a chkdsk   on the drives?
Question: Are you using RAID that was setup in the adapter (called Hardware RAID), or, are you using RAID that was setup in Windows? I am guessing hardware...

This could be because you have a "degraded" RAID array. I would look for any light on the drives that is not green. If you find an amber or red light, pull that drive and then re-insert it. If it goes green and stays green, then RAID will repair the array and after that completes you will be fine.

Let me know if this is helpful or not.
Avatar of tmoore1962
tmoore1962

Most likely you would benefit greatly with better HDD's I like to use at least 10k drives for servers 15k drives on SBS because they have so much running in background you don't want the server waiting on Disk I/O particularly since you have a RAID 5 array which isn't known for blazing disk write performance in the first place.  Remember beside your file copying the HDD's are logging your Exchange emails and logs, share points logs, WSUS updates on SBS 2011 if everything is configured.  But if you want to bench mark your HDD's one of these should do it:
ATTO Benchmark: http://www.attotech.com/products/product.php?sku=Disk_B...

 HDTune: http://www.hdtune.com/

 CrystalDiskMark: http://crystalmark.info/software/CrystalDiskMark/index-...
Avatar of Adam D

ASKER

Thank you for your replies.

1 & 2. No, I have not done a chkdsk on the drives; however; both Intel's storage management, HD Sentinel and Windows itself ALL say the drives, raid setup, configuration, etc. are fine.  No problems are being shown at all in any of the monitoring tools.

3. While I would benefit from faster drives that is not the cause of my speed issue.  I have similar drives in other servers without issue.  This is something else.

What tools, tests can I run on every component of this machine to find out what is causing this problem?

Thanks.
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Don Thomson
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Avatar of Adam D

ASKER

Thanks DTH.

This was a cheap build for a low use server and while ECC memory is an added bonus, with today DRAM chip reliability it is not an absolute necessity.  :)

Copying a 900MB file from C to C started out well at 60MB / sec then dropped to 10 MB / sec - no spikes in network or RAM and CPU usage stayed constant.

Copying the same file from C to D started out about 25 MB / sec then dropped to 8 MB / Sec, again no spikes elsewhere.

At the end of the C to C copy network usage spiked for 10 seconds - but it may have been something else.

I have not tested from a memory stick/external HDD yet.

I can run a chkdsk this weekend just not during the work week.

Are there any tools that can give me in-depth information through Windows? There must be something that can assess the system.

Thanks.
The initial high transfer speed is to cache, but the real disk speed is shown in the second phase.

Looks like a a disk/disk config issue.

How are the disks configured? Are you using hardware or software RAID?
Avatar of Adam D

ASKER

Hardware RAID 5.
Well that might be the problem as i think your config uses a fake-RAID controller which are notoriously slow.

Your system would probably perform much better if you add another drive and convert to RAID10 in software.
Avatar of Adam D

ASKER

RAID10 might decrease some latency but would not fix this particular problem.

As for the software vs hardware RAID - I don't know if there is a software version overriding the hardware version - how would I tell?

I have another server with a very similar setup with no issues.
Remember both C and D are on the same physical drive, the drives will be caching a lot since the same physical drive is doing both the writing and reading, get a usb drive and retest read write, the only hardware issue that you may have would be one of the drives in the array may have a cache memory issue,  I have ran into a few hard drives with performance issues such as system slow downs and pauses the HDD will pass the manufacturers HDD tests but when replaced with Identical drive the issue is resolved, if you have a spare hard drive for the array you can replace one at a time and after the raid rebuild rerun the tests to see if issue resolved, have not been able to find any tests that test a hard drives cache.
Raid Hardware is usually configured at startup and during a restart of the system, you will be prompted to enter the raid bios. If you are running raid 5 in a software configuration then the configuration would be normally done inside windows.

The Hardware Raid 5 usually has it's own controller and it's own cache memory. The more the better.  With Hardware Windows sees the drives as a single drive.
Have you run chkdsk on this system yet?

It really looks like you have a disk write issue, especially as the hardware tests you have run are showing inconsistent rates.

The fake-RAID controller in this system running RAID-5 is going to be slower than RAID10 especially if the RAID10 is implemented in software.

Is this a DIY system? have you looked at what the SMART counters on the disks say?
Avatar of Adam D

ASKER

One of the three drives had "weak sectors" which was causing the problem.