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I am trying to get write caching enabled on a Smart Array P400 even though there is no battery backup. We have a large building wide UPS backed up by a generator so the likelihood of loosing power is minimal and the write performance on this VM host server is terrible. I have installed the HP VMware drivers and software and I have used hpssacli to turn on write caching and no-battery write cache:

/opt/hp/hpssacli/bin # ./hpssacli controller slot=1 show config detail

Smart Array P400 in Slot 1
   Bus Interface: PCI
   Slot: 1
   Serial Number: PAFGK0P9VX029O
   Cache Serial Number: PA82C0J9VX12T7
   RAID 6 (ADG) Status: Disabled
   Controller Status: OK
   Hardware Revision: E
   Firmware Version: 7.22
   Rebuild Priority: Medium
   Expand Priority: Medium
   Surface Scan Delay: 15 secs
   Surface Scan Mode: Idle
   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: Enabled
   Total Cache Size: 256 MB
   Total Cache Memory Available: 208 MB
   No-Battery Write Cache: Enabled
   Battery/Capacitor Count: 0
   SATA NCQ Supported: True
   Number of Ports: 2 Internal only
   Encryption Supported: False
   Driver Version: 3.6.14
   Driver Supports HP SSD Smart Path: False


   Internal Drive Cage at Port 1I, Box 1, OK
      Power Supply Status: Not Redundant
      Serial Number:
      Drive Bays: 4
      Port: 1I
      Box: 1
      Location: Internal

   Physical Drives
      physicaldrive 1I:1:7 (port 1I:box 1:bay 7, SATA, 250 GB, OK, spare)
      physicaldrive 1I:1:6 (port 1I:box 1:bay 6, SATA, 250 GB, OK)
      physicaldrive 1I:1:5 (port 1I:box 1:bay 5, SATA, 250 GB, OK)


   Internal Drive Cage at Port 2I, Box 1, OK
      Power Supply Status: Not Redundant
      Serial Number:
      Drive Bays: 4
      Port: 2I
      Box: 1
      Location: Internal

   Physical Drives
      physicaldrive 2I:1:4 (port 2I:box 1:bay 4, SATA, 250 GB, OK)
      physicaldrive 2I:1:3 (port 2I:box 1:bay 3, SATA, 250 GB, OK)
      physicaldrive 2I:1:2 (port 2I:box 1:bay 2, SATA, 250 GB, OK)
      physicaldrive 2I:1:1 (port 2I:box 1:bay 1, SATA, 120 GB, OK)

   Array: A
      Interface Type: SATA
      Unused Space: 0  MB
      Status: OK
      Array Type: Data



      Logical Drive: 1
         Size: 111.8 GB
         Fault Tolerance: 0
         Heads: 255
         Sectors Per Track: 32
         Cylinders: 28722
         Strip Size: 128 KB
         Full Stripe Size: 128 KB
         Status: OK
         Caching:  Enabled
         Unique Identifier: 600508B10010503956583032394F0009
         Logical Drive Label: A0199599PAFGK0P9VX029O81A9
         Drive Type: Data
         LD Acceleration Method: Controller Cache

      physicaldrive 2I:1:1
         Port: 2I
         Box: 1
         Bay: 1
         Status: OK
         Drive Type: Data Drive
         Interface Type: SATA
         Size: 120 GB
         Native Block Size: 512
         Firmware Revision: HPG2
         Serial Number: K647T8B25P5U
         Model: ATA     GJ0120CAGSP
         SATA NCQ Capable: True
         SATA NCQ Enabled: True
         Current Temperature (C): 33
         Maximum Temperature (C): 58
         PHY Count: 1
         PHY Transfer Rate: 1.5Gbps


   Array: B
      Interface Type: SATA
      Unused Space: 0  MB
      Status: OK
      Array Type: Data
      Spare Type: dedicated



      Logical Drive: 2
         Size: 931.4 GB
         Fault Tolerance: 5
         Heads: 255
         Sectors Per Track: 32
         Cylinders: 65535
         Strip Size: 64 KB
         Full Stripe Size: 256 KB
         Status: OK
         Caching:  Enabled
         Parity Initialization Status: Initialization Completed
         Unique Identifier: 600508B10010503956583032394F000A
         Logical Drive Label: A01986FDPAFGK0P9VX029O8FA7
         Drive Type: Data
         LD Acceleration Method: Controller Cache

      physicaldrive 1I:1:5
         Port: 1I
         Box: 1
         Bay: 5
         Status: OK
         Drive Type: Data Drive
         Interface Type: SATA
         Size: 250 GB
         Native Block Size: 512
         Firmware Revision: HPG2
         Serial Number: K648TAC28P4N
         Model: ATA     GJ0250EAGSQ
         SATA NCQ Capable: True
         SATA NCQ Enabled: True
         Current Temperature (C): 35
         Maximum Temperature (C): 58
         PHY Count: 1
         PHY Transfer Rate: 1.5Gbps

      physicaldrive 1I:1:6
         Port: 1I
         Box: 1
         Bay: 6
         Status: OK
         Drive Type: Data Drive
         Interface Type: SATA
         Size: 250 GB
         Native Block Size: 512
         Firmware Revision: HPG2
         Serial Number: K648T8C25MF2
         Model: ATA     GJ0250EAGSQ
         SATA NCQ Capable: True
         SATA NCQ Enabled: True
         Current Temperature (C): 34
         Maximum Temperature (C): 58
         PHY Count: 1
         PHY Transfer Rate: 1.5Gbps

      physicaldrive 2I:1:2
         Port: 2I
         Box: 1
         Bay: 2
         Status: OK
         Drive Type: Data Drive
         Interface Type: SATA
         Size: 250 GB
         Native Block Size: 512
         Firmware Revision: HPG2
         Serial Number: K648T8C25MFW
         Model: ATA     GJ0250EAGSQ
         SATA NCQ Capable: True
         SATA NCQ Enabled: True
         Current Temperature (C): 35
         Maximum Temperature (C): 58
         PHY Count: 1
         PHY Transfer Rate: 1.5Gbps

      physicaldrive 2I:1:3
         Port: 2I
         Box: 1
         Bay: 3
         Status: OK
         Drive Type: Data Drive
         Interface Type: SATA
         Size: 250 GB
         Native Block Size: 512
         Firmware Revision: HPG2
         Serial Number: K648T8B25M9W
         Model: ATA     GJ0250EAGSQ
         SATA NCQ Capable: True
         SATA NCQ Enabled: True
         Current Temperature (C): 35
         Maximum Temperature (C): 58
         PHY Count: 1
         PHY Transfer Rate: 1.5Gbps

      physicaldrive 2I:1:4
         Port: 2I
         Box: 1
         Bay: 4
         Status: OK
         Drive Type: Data Drive
         Interface Type: SATA
         Size: 250 GB
         Native Block Size: 512
         Firmware Revision: HPG2
         Serial Number: K648T8C25ML9
         Model: ATA     GJ0250EAGSQ
         SATA NCQ Capable: True
         SATA NCQ Enabled: True
         Current Temperature (C): 35
         Maximum Temperature (C): 58
         PHY Count: 1
         PHY Transfer Rate: 1.5Gbps

      physicaldrive 1I:1:7
         Port: 1I
         Box: 1
         Bay: 7
         Status: OK
         Drive Type: Spare Drive
         Interface Type: SATA
         Size: 250 GB
         Native Block Size: 512
         Firmware Revision: HPG2
         Serial Number: K648T8C25MK0
         Model: ATA     GJ0250EAGSQ
         SATA NCQ Capable: True
         SATA NCQ Enabled: True
         Current Temperature (C): 31
         Maximum Temperature (C): 57
         PHY Count: 1
         PHY Transfer Rate: 1.5Gbps

But as you can see, the cache ratio is 0% for writes. What am I missing?

2

It looks like this looks like what you are looking for:

ctrl slot=0 cacheratio=50/50

source: https://community.hpe.com/t5/ProLiant-Servers-ML-DL-SL/Smart-Array-Controller-P400-cache-ratio/td-p/4018686

  • That was it, thanks! For clarity, the actual command is /opt/hp/hpssacli/bin/hpssacli controller slot=1 modify cacheratio=50/50. – Caynadian Apr 29 '17 at 12:24
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This is a tacky solution.

The HP Smart Array P400 doesn't really honor the no-battery cache override setting.

  • But the use of a Smart Array P400 means you're using an HP ProLiant G5 server...
  • Which means you're using something from the 2005-2008 era... 10 years old.
  • Which indicates that you're running something that VMware doesn't support anymore...
  • And SATA drives downshift their speed to 1.5Gbps (instead of 3Gbps or 6Gbps) on that controller; half the speed of a SAS drive...
  • Which means your performance is going to be really, really poor... even WITH write cache.

You could try to find a battery, but the server is so old that nobody had a stock of new healthy batteries.

And since the street value of a server of that generation is about $100, it's a tough use case.

Are you sure you want to run this particular server?

  • It is an old server that runs some non-essential VMs. Mostly testing and monitoring stuff. I am going to replace it next budget cycle but I'm just trying to get a little better performance out of it until then. – Caynadian Apr 29 '17 at 12:22
  • I understood that this hardware was old, maybe not as specifically as you. I am just starting out on this site, so I am trying to understand the best way to handle things. Should I not help a user if it is "not worth working on"? He seems to understand the risks of no battery cache, and just wanted help with the ratio issue. – Cory Knutson Apr 29 '17 at 12:44

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