BackupPC-users

Re: [BackupPC-users] rsyncd full backup

2013-10-30 22:35:56
Subject: Re: [BackupPC-users] rsyncd full backup
From: Adam Goryachev <mailinglists AT websitemanagers.com DOT au>
To: backuppc-users AT lists.sourceforge DOT net
Date: Thu, 31 Oct 2013 13:34:52 +1100
On 31/10/13 13:06, Sharuzzaman Ahmat Raslan wrote:
> Hi Holger,
>
> Based on short session of troubleshooting, I believe the machine
> actually suffer from low I/O speed to the disk. Average read is about
> 3 MB/s, which I considered slow for a SATA disk in IDE emulation.

Is that under load, or while idle? If it is under load, then it might be 
expected, remember throughput is very bad for HD when you have random 
load due to seek times.

If it is idle and has that performance level, then there is something 
wrong. Even old IDE disks could do at least 30 to 50MB/s for large 
contiguous reads.

> I'm planning to suggest to the customer to have a RAID 1 setup to
> increase the I/O speed. I'm looking at possibilities to speed things
> up by not having to change the overall setup.
While RAID1 will assist in reliability and is one strategy to reduce 
downtime/data loss (but it isn't a backup), it also is not going to 
improve performance. With RAID1 you still need to write to both disks, 
and while it is theoretically possible to balance reads across both 
disks, it likely won't do that well without a proper hardware raid 
controller.

Personally, my suggestion would be to consider using a SSD, since you 
are using such an old drive, probably you don't need a lot of space, so 
a 120GB SSD might be suitable. An SSD will handle random IO 
significantly better than any one or two drive system, with much higher 
transfer rates as well (there is no penalty for seek times with SSD).

Again, personally, I've used a couple of systems with 5 x 480GB Intel 
520s SSD in RAID5, and they have been working really well (except they 
were difficult to actually get stock of them most of this year, and I 
hear they are now replaced by a new model).

Regards,
Adam

-- 
Adam Goryachev
Website Managers
P: +61 2 8304 0000                    adam AT websitemanagers.com DOT au
F: +61 2 8304 0001                     www.websitemanagers.com.au


-- 
Adam Goryachev Website Managers www.websitemanagers.com.au

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