Re: [vserver] btrfs/hashify/cow....

From: Gordan Bobic <gordan_at_bobich.net>
Date: Mon 10 Sep 2012 - 12:02:53 BST
Message-ID: <504DC8DD.6040903@bobich.net>

On 09/10/2012 01:42 AM, John A. Sullivan III wrote:

>>> If so, I think it would be even better than OpenSolaris
>>> as it appears the network stack latency is lower in Linux than
>>> OpenSolaris from what we've seen. Thanks - John
>>
>> ZFS doesn't go anywhere near the network stack so I don't know what
>> exactly the connection here might be.
>
> Network latency for IOPS in a SAN. For small block sizes, I would think
> latency would be even more of an issue than bandwidth when talking to a
> ZFS based SAN. Then again, I suppose command tag queuing would coalesce
> those so latency would not be as critical.

Latency (ping time) on a typical Gbit network is < 100us. Latency of a
15,000rpm disk is 4ms. That's a 40x difference. I don't see the network
latency being particularly relevant at between 1-2.5% of your disk
latency (depending on the speed of your disks).

Gordan
Received on Mon Sep 10 12:03:04 2012

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