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PowerEdge R7525: IO sequential read throughput drops when testing with over 10 SSD drives simultaneously

Summary: PowerEdge R7525 with PowerEdge RAID Controller (H345, H745) experiences a significant I/O throughput drop during sequential read testing with over 10 SSD drives in non-RAID mode.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Symptoms

See Figure 1, which shows sequential read throughput with 10 SATA SSDs. Each SSD achieved 530 MB/s,
Totaling 5.3 GB/s

See Figure 2, which shows sequential read throughput with 12 SATA SSDs. 4 SSDs achieved 430 MB/s, the other 8 achieved 220 MB/s,
Totaling 3.5 GB/s 


Sequential Read throughput on 10 SATA SSDs
Figure 1: Sequential Read throughput on 10 SATA SSDs

Sequential Read throughput on 12 SATA SSDs
Figure 2: Sequential Read throughput on 12 SATA SSDs

Cause

The default BIOS setting is not optimized for I/O performance.
Red Hat Enterprise Linux (RHEL) 8.3 has storage performance improvements that are unavailable in Red Hat Enterprise Linux 7.x.
PERC H345 and H745 are PCIe Gen3 x8 devices. The maximum throughput is 7GB/s.

Resolution

Install Red Hat Enterprise Linux 8.3 or newer for I/O performance testing.
Follow these instructions for BIOS SETUP tuning:
  1. Boot into BIOS Setup and press Alt-F2 to load the default setting.
  2. Navigate to 'Processor Settings'. Disable 'Virtualization Technology', set 'MADT Core Enumeration' to 'Round Robin', and 'Numa Nodes Per Socket' to 4 (See Figure 4).
  3. Go to 'System Profile settings'. Set 'System Profile' to Custom, 'CPU Power Management" to 'Maximum Performance', 'C State' to 'Disabled' and 'Determinism Slider' to 'Performance Determinism' (See Figure 5).

BIOS Setup: Processors Settings
Figure 3: BIOS Setup: Processors Settings

BIOS Setup: System Profile Settings
Figure 4: BIOS Setup: System Profile Settings

Affected Products

PowerEdge RAID Controller H345, PowerEdge RAID Controller H745, PowerEdge R7525
Article Properties
Article Number: 000221862
Article Type: Solution
Last Modified: 21 Feb 2024
Version:  1
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