Samsung 850 EVO + HP P410 limited iops?
I´m experiencing a weird write iops limitation with a HP P410 256mb cache controller and 4x consumer grade ssd´s (Samsung EVO 850) in RAID5/10. After upgrade to latest firmware (6.64) for HP P410 controller, it continues with problems.
Iostat output:
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
sda 0.00 0.00 1.00 158.00 36.00 15631.00 197.07 12.16 75.84 6.00 76.28 6.30 100.10
158 writes/s and 100 % util.
My hpacucli output:
=> ctrl all show config detail
Smart Array P410 in Slot 2
Bus Interface: PCI
Slot: 2
Serial Number: PACCR9SYLZ34
Cache Serial Number: PACCQ9SYP5CK
RAID 6 (ADG) Status: Disabled
Controller Status: OK
Hardware Revision: C
Firmware Version: 6.62
Rebuild Priority: Medium
Expand Priority: Medium
Surface Scan Delay: 15 secs
Surface Scan Mode: Idle
Queue Depth: Automatic
Monitor and Performance Delay: 60 min
Elevator Sort: Enabled
Degraded Performance Optimization: Disabled
Inconsistency Repair Policy: Disabled
Wait for Cache Room: Disabled
Surface Analysis Inconsistency Notification: Disabled
Post Prompt Timeout: 0 secs
Cache Board Present: True
Cache Status: OK
Cache Ratio: 100% Read / 0% Write
Drive Write Cache: Disabled
Total Cache Size: 256 MB
Total Cache Memory Available: 144 MB
No-Battery Write Cache: Disabled
Battery/Capacitor Count: 0
SATA NCQ Supported: True
Array: A
Interface Type: Solid State SATA
Unused Space: 0 MB
Status: OK
Array Type: Data
Logical Drive: 1
Size: 698.6 GB
Fault Tolerance: RAID 5
Heads: 255
Sectors Per Track: 32
Cylinders: 65535
Strip Size: 256 KB
Full Stripe Size: 768 KB
Status: OK
Caching: Enabled
Parity Initialization Status: Initialization Failed
Unique Identifier: 600508B1001C8929D0C6820FB103773E
Disk Name: /dev/sda
Mount Points: None
Logical Drive Label: A516FD0DPACCR9SYLZ3435C0
Drive Type: Data
physicaldrive 1I:1:1
Port: 1I
Box: 1
Bay: 1
Status: OK
Drive Type: Data Drive
Interface Type: Solid State SATA
Size: 250 GB
Firmware Revision: EMT01B6Q
Serial Number: S21PNSAG270000F
Model: ATA Samsung SSD 850
SATA NCQ Capable: True
SATA NCQ Enabled: True
Current Temperature (C): 30
Maximum Temperature (C): 70
SSD Smart Trip Wearout: Not Supported
PHY Count: 1
PHY Transfer Rate: 3.0Gbps
physicaldrive 1I:1:2
Port: 1I
Box: 1
Bay: 2
Status: OK
Drive Type: Data Drive
Interface Type: Solid State SATA
Size: 250 GB
Firmware Revision: EMT01B6Q
Serial Number: S21PNSAG269993V
Model: ATA Samsung SSD 850
SATA NCQ Capable: True
SATA NCQ Enabled: True
Current Temperature (C): 32
Maximum Temperature (C): 70
SSD Smart Trip Wearout: Not Supported
PHY Count: 1
PHY Transfer Rate: 3.0Gbps
physicaldrive 1I:1:3
Port: 1I
Box: 1
Bay: 3
Status: OK
Drive Type: Data Drive
Interface Type: Solid State SATA
Size: 250 GB
Firmware Revision: EMT01B6Q
Serial Number: S21PNSAG269984Z
Model: ATA Samsung SSD 850
SATA NCQ Capable: True
SATA NCQ Enabled: True
Current Temperature (C): 31
Maximum Temperature (C): 70
SSD Smart Trip Wearout: Not Supported
PHY Count: 1
PHY Transfer Rate: 3.0Gbps
physicaldrive 1I:1:4
Port: 1I
Box: 1
Bay: 4
Status: OK
Drive Type: Data Drive
Interface Type: Solid State SATA
Size: 250 GB
Firmware Revision: EMT01B6Q
Serial Number: S21PNSAG269998N
Model: ATA Samsung SSD 850
SATA NCQ Capable: True
SATA NCQ Enabled: True
Current Temperature (C): 31
Maximum Temperature (C): 70
SSD Smart Trip Wearout: Not Supported
PHY Count: 1
PHY Transfer Rate: 3.0Gbps
SEP (Vendor ID PMCSIERA, Model SRC 8x6G) 250
Device Number: 250
Firmware Version: RevC
WWID: 500143800694906F
Vendor ID: PMCSIERA
Model: SRC 8x6G
Someone has experienced this problem with HP P410?
Solution 1:
There are a few issues here.
- You don't have any controller write cache or a battery-backed or flash-capacitor.
- The HP Smart Array P410 controller is limited in IOPS capacity. It's not a good match for SSDs.
- Using SATA drives on a Smart Array P410 causes the interface speed to downshift to 3.0Gbps instead of 6.0Gbps.
- Please try with RAID 1+0. RAID5 is not good for this combination of equipment.
- Also, your RAID5 parity initialization failed, according to your
hpssaclioutput.
Parity Initialization Status: Initialization Failed
HP's best practices for SSDs on that controller are listed here.
Also see: SSD (Intel 530) read/write speed very slow with RAID 10 and HP ACU shows parity initialization failed on Smart Array controller
Solution 2:
MLC SSD really need a fast private DRAM cache for delivering high IOPS values.
While your controller has its own cache and it is enabled, your disk's private DRAM cache is disabled. This is a safety measure, as enabling that unprotected (from power losses) cache can put your data at risk.
Sometime it is safe to reenable it (eg: your disks has power loss protection, or your controller correctly propagate ATA FLUSH / FUA commands to the downstream disks), but you can't be 100% sure without testing. Some RAID controller even do not permit to reenable the disk's private DRAM cache.
For testing purpose, you can try to reenable it and re-test your array, but be very careful to put it into production. When possible, use SSD with power loss protection (Crucial M550/M600 have a partial protection, while Intel S3500/3700/DC series have full power protection).