Drive configuration in HP DL380 Gen 9


I was hoping for some advice on drives and configuration for a server I want to spec up.

The server is an HP DL380 Gen 9. part number: 826684-B21

The RAID card in the controller is a HP Smart Array P440ar/2GB FBWC 12Gb 1-port Int SAS Controller

I want to put a second internal drive cage for additional storage. But the RAID controller only supports 8 connections (the bay already in there)

I have been told a SAS expander card will do this for me (part number: 727250-B21): I understand this will allow me to fulfil 16 connections... is this correct?

I would like to run 5 times 1.2 TB 10K SAS drives in a RAID 1+0 (with one spare) in drive cage 1. This will be for the operating systems of 4-5 virtual servers (DC, File, Exchange and SQL (SQL DB and logs will be on a different array). I have been led to believe that 10K drives will suffice for this job and to ensure I have a lot of memory. is this true? I think single or dual port drives makes no difference in this config? Also, what about 6G or 12G... I have seen 2 part numbers 781518-B21 and 718162-B21 and the price is pretty much identical. Do I need 12G because the raid controller is 12G?

On the second drive cage I wanted to run 2 arrays. 2 * 480GB SATA SSD's in RAID 1 (twice over) and a hot spare (5 drives in total). 1 array for SQL log files and 1 for SQL Database. Having separate RAID arrays was recommended for the SQL application.

Obviously SATA SSD are about half the price of SAS SSD's! I have read differing opinions. Is this a false economy? I thought running the SATA drives (they will be HP enterprise SATA drives) in a mirror would be ok... I understand they can have problems in RAID 5-6 configurations?

Thanks for any help
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You can indeed buy the SAS expander to allow both cages to be run from one controller. It makes a right rat's nest of cables - p440 to expander (2) then expander to cages (4) but it does work. If you don't need to spread disks across both cages though a second PCIe Smart Array controller is superior as you get twice as much cache and fewer cables so better airflow.

You can't get single port disks any more, they were only made in the first iteration of 3Gb disks. Only one port will be used on your disks admittedly as there's only one lane per disk available but it's not worth the manufacturer's making single and dual port variants.

You don't put transaction logs on SSDs, the logs are sequential and spinning disks are great at sequential data. SSDs are to eliminate random access latency.

If you can keep it down to 8 rotating disks and 8 SSDs then rather than a second RAID controller you may be better using a dumb HBA and software RAID on the SSDs.
sfabsAuthor Commented:
Hi Andy

Thank you for your help, I am glad you replied as I had researched a number of questions in the area and found your answers on those questions to be very good.

You have addressed a number of concerns and I appreciate that.

I will take your advice on using spinning disks for  transactions logs. Do you fell it is worth using SSD for the SQL database (there will be a balance of reading and writing). Would SATA SSD in a RAID 1 be ok (480GB disks) or do you feel SAS is the only way to go for SSD's in any sort of RAID?

Do you have any concerns regarding using 4 times 1.2TB 10K SAS disks in a RAID 1+0 configuration for the virtualisation of 4 servers? SOmeone suggested I would be better off with 15K disks but the largest 15K disks are 600MB. I understood that with a lot of memory I wouldnt have a problem that they were 10K disks?

thank you again for your time and help

I appreciate the advice on the RAID controller and will also take your advice on a second P440 card instead of the expander card. I wish I could cut down to under 8 drives but I don't see it as a possibility with the numerous arrays requested.
This expert suggested creating a Gigs project.
I cant see anything wrong with 10k disks for the OS and executables, once loaded there is not much disk activity on OS disks unless AD is on C:.

There may be more difference between the SSDs apart from the interface. What part nos are you considering? I can then look up the spec later.

There is a gaster alternative to SSDs for the database files but it's evenmore expensive. HP sell Fusion io PCIe flash cards under I/O accelerator brand name. No SAS or SATA interface to slow them down
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I didnt suggest creating a gig, I dropped my phone and pressed a few buttons picking it up!
sfabsAuthor Commented:
Phew, that's a relief... a gigs project did sound like a fair amount of work :)

Thanks again for replying Andy.

Thanks for your opinion on the SAS 10K disks... I was thinking that but it's great to see you feel the same.

I am considering SATA SSD's instead of SAS SSD's to save cost... I would love to go for HP Fusion but don't want to increase cost.

The factory installed P440 controller will be responsible for the 5 * 1.2TB  (OS array) in a RAID 1+0

Having considered your advice I want to install a second p440 (726736-B21) which is listed as a PCi Express, I think it is identical to the installed card and I believe the server can fit both...?

In the second array card I will create a RAID 1 array for log files as per your advice, using spinning disks, AND create a  RAID 1 using the following SATA SSD's for the database; the part number I currently like: 764927-B21 is available at a very good price. Do you think this drive is suitable for the application? (30-40 users reading and writing to an ERP database, I thought the IOPS from an SSD would improve performance of DB)
A second P440 will be fine for the second cage, it's the same as the imbedded controller just on a PCIe card. HP don't have a limit to the number of RAID controllers in the servers, some used to have a dozen in them for benchmark tests. 726907-B21 may do though if you're happy to use software RAID for the second cage, I think all your non-SSD disks will fit in the first cage?

 764927-B21 mixed usage drive looks OK to me for the DB, there's normally more reading than writing with databases. If you do run a high write environment and you burn it out before 3 years then as long as it isn't too expensive you just have to buy another one as they won't cover it under warranty.
sfabsAuthor Commented:
Thank you Andy

Yes you are correct... I could fit 8 spinning drives (OS array and SQL logs array with spares) into drive cage 1 plugged into the supplied P440.

Then that seems like a good option of Software RAID on cage 2 for the SATA SSD's running the SQL database. Can i expect the same sort of performance as the hardware RAID of the 440?

I don't expect it to be an exceptionally high write environment, it is an ERP system. Either way I can swallow the price of a replacement drive if it came to it.

Andy thank you very much, my spec has changed considerably from start to finish and I am much more confident now with the spec. The above question is my last
There's a paid for option for the RAID controller called Smart Path that bypasses the RAID controller for reads because it's faster for the driver to access the SSDs directly than for it to go through the RAID chip - the RAID chip actually slows it down. Using the HBA achieves the same thing at a much lower cost. You can also enable TRIM if you use an HBA with software mirroring rather than a RAID controller, TRIM reduces wear by telling the SSD what blocks it can erase so there's less background shuffling of data on the SSD.
sfabsAuthor Commented:
thank you for all your help. Brilliant help Andy
sfabsAuthor Commented:
brilliant level of knowledge and help, thank you Andy
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