I want to ask you a advice or what to do with the following case.
We have a couple of IBM x3650 M3 with these specs:
- x3650 M3, 2 x Xeon 6C X5675 95W 3.06GHz/1333MHz/12MB,
- ServeRAID M5015;
- 8GB (1x8GB, 2Rx4, 1.5V) PC3-10600 CL9 ECC DDR3 1333MHz LP RDIMM;
- 2 x Express IBM 146 GB 2.5in SFF Slim-HS 15K 6Gbps SAS HDD;
- 2 x IBM 6Gb SAS HBA;
- Intel Ethernet Dual Port Server Adapter I340-T2 for IBM System x;
- IBM 675W High Efficiency Redundant AC Power Supply;
- IBM Virtual Media Key.
OS was installed on local RAID 1, which was created with the ServeRAID M5015 and 2 x Express IBM 146 GB HDDs.
The problem. We have a reduced throughput with the local disks on the servers, and disks on DS3512 connected to these servers with IBM 6Gb SAS HBAs.
In brief – tests (IOMeter, HD_Speed) have shown out that the throughput is equal ~ 3 Gbit/seconds, when we were testing both local disks, and disks on DS3512 connected to these servers.
Physically all equipment (disks, local RAID-controlers, DS3512) corresponds to the SAS 2.0 standard, or 6 Gbit/seconds. Theoretically I should receive something about 5 Gbit/seconds, but all what I have ~ 3 Gbit/seconds.
This speed I receive on different operating systems – Windows Server 2008 R2 SP1 and VMware ESXi 5 UP1 (I've been testing a virtual machine under its management), so it is obvious that something wrong with the servers.
All settings in BIOS were configured for the maximum performance, C-states are disabled. In the system logs both on servers and DS3512 everything is ok, the established speed of all interfaces - 6 Gbit/seconds. Where is the problem is unclear...
I've opened a case with the IBM's technical support, and sent them all logs that they have required, but as they told me - it is your problem that you cannot achieve
speed 5 Gbit/seconds when testing your disks.
Very funny, I have a 3-years old server with the SAS 1.0 disks and RAID controller and I get ~ 2,2 Gbit/seconds in comparing with 3 Gbit/seconds on the newest x3650 M3 server...
Please, help to resolve this issue :(