Backup Speed Disparity

The technical support forum for Firestreamer (the virtual tape library).
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AFlowers
Posts: 2
Joined: 16 Sep 2010, 13:35

Backup Speed Disparity

Post by AFlowers » 16 Sep 2010, 14:01

Hi,
I tested and began using Firestreamer with DPM using a 5-drive eSATA enclosure, 1.5TB disks. Each disk will hold the night's backup. Everything works great! The nightly backup will take about 5.5 hours for about 460GB data.

Since DPM forces us to make backups on the weekend whether we want to or not, the 5-drive setup was not enough for a 7-day week. So, I bought an identical 5-drive enclosure, installed an identical set of drives, and plugged it into the second port on the same eSATA card as the first enclosure.

My problem: Backups made to drives in the first enclosure take about 5.5 hours. Backups made to drives in the second enclosure take over 10 hours! Same data, same everything else.

This may not be (and is problably not) a Firestreamer problem. However, I hope you can tell me where to start looking.

Any ideas?

Thanks in advance!

jsf
Cristalink Support
Posts: 300
Joined: 29 Aug 2010, 09:03

Re: Backup Speed Disparity

Post by jsf » 16 Sep 2010, 22:20

The problem is unlikely to relate to Firestreamer. We are working on an article on performance issues, which will be posted to the FAQ forum soon.

Meanwhile, I suggest the following. Let's assume that you have fast Enclosure 1 (E1) connected to eSATA port 1, and slow Enclosure 2 (E2) connected to port 2.
  1. Try updating the enclosure firmware, if possible at all, to see if it helps.
  2. Disconnect the enclosure cables at the server side, and connect E1 to port 2, and E2 to port 1.
  3. Perform test backups to both enclosures. If E1 is still fast and E2 is still slow, then the problem is in E2. If E1 became slow, and E2 became fast, then the problem is in the server (this includes the eSATA controller).
If the problem is in the enclosure, then:
  1. Try swapping the cables to see if the problem is in a cable.
  2. Swap the groups of disks between E1 and E2 to see if the problem is in the disks or the enclosure itself.
If the problem is in the server, check the Windows settings (in particular, in Device Manager > Properties) and controller settings (check the BIOS and/or the GUI configuration utility), to see if the port settings are different.
Best regards,
John Smith
Cristalink Support

AFlowers
Posts: 2
Joined: 16 Sep 2010, 13:35

Re: Backup Speed Disparity

Post by AFlowers » 17 Sep 2010, 14:21

Good suggestions, John!

They are identical enclosures. However, it makes sense to just move things around and see if the performance moves. I will do that.

I look forward to your article on performance.

Thanks!

jsf
Cristalink Support
Posts: 300
Joined: 29 Aug 2010, 09:03

Re: Backup Speed Disparity

Post by jsf » 20 Dec 2010, 09:29

Best regards,
John Smith
Cristalink Support

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