Significant performance degradation during transfer

[EightySix Four]

We're doing a data copy from a RAID 10 array of 4 drives to a Synology NAS attached by GbE with 4 2TB drives in RAID 5. During the transfer, the initial burst speed is fantastic, around 100MB/s, but after 1-5 minutes it drops to around 7MB/s and never speeds back up. Other transfers using the RAID 10 drive can sustain over 100MB/s without problem and the NAS + drives are brand new.

We've tried NFS and CIFS for mounting and rsync, CP, and CPIO for the copy. The NAS is connected directly to the ethernet port with a Cat 6 crossover cable.

Anyone have any suggestions?

 

[EightySix Four]

Solution found: reboot the server. It had been running for ~3 years without reboot.

 

[azazel1024]

That is an impressive record of uptime. I reboot mine weekly, just to be sure.

It fixed it for you, but I was going to mention, any chance of fragmentation?