On Tue, Jan 30, 2018 at 10:00:44AM +0100, Reindl Harald wrote:
Am 30.01.2018 um 09:49 schrieb Terry Barnaby:
Untar on server to its local disk: 13 seconds, effective data rate: 68 MBytes/s
Untar on server over NFSv4.2 with async on server: 3 minutes, effective data rate: 4.9 MBytes/sec
Untar on server over NFSv4.2 without async on server: 2 hours 12 minutes, effective data rate: 115 kBytes/s !!
Is it really expected for NFS to be this bad these days with a reasonably typical operation and are there no other tuning parameters that can help ?
no, we are running a virtual backup appliance (VMware Data Protection aka EMC Avamar) on vSphere 5.5 on a HP microserver running CentOS7 with a RAID10 built of 4x4 TB consumer desktop disks and the limiting factor currently is the Gigabit Ethernet
35 TB network IO per month, around 1 TB per day which happens between 1:00 AM and 2:00 AM as well as garbage collection between 07:AM and 08:00 AM
Again, this is highly dependent on the workload.
Your backup appliance is probably mainly doing large sequential writes to a small number of big files, and we aim for that sort of workload to be limited only by available bandwidth, which is what you're seeing.
If you have a single-threaded process creating lots of small files, you'll be limited by disk write latency long before you hit any bandwidth limits.
--b.
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J. Bruce Fields