SQL Server Performance

146GB vs. 72GB Sustained read speeds

Discussion in 'SQL Server 2005 Performance Tuning for Hardware' started by egmiii, Apr 16, 2007.

  1. egmiii New Member

    I'm looking to purchase a new HP ML370 G5, with the external MSA50 enclosure. I'm debating between the 72GB and 146GB 2.5" 10,000 RPM drives. The 72s provide adequate storage, but I'd like the know if the 146s have a higher sustained read speed. I thought they had twice as many platters, which would indicate they could sustain double the read speed. Are my assumptions way off? Thanks.
  2. satya Moderator

    How about database growth?
    How about accessibility on Application, any highs or lows?
    Is database design optimized to serve the resource intensive queries?

    http://www.sql-server-performance.com/forum/topic.asp?TOPIC_ID=16995 fyi.

    Satya SKJ
    Microsoft SQL Server MVP
    Writer, Contributing Editor & Moderator
    This posting is provided AS IS with no rights for the sake of knowledge sharing. The greatest discovery of my generation is that a human being can alter his life by altering his attitudes of mind.
  3. egmiii New Member

    Our database is about 80GB and grows a GB or less per month. A 10 drive RAID 10 array will give me 360GB (using 72s), which is plenty. So 146s are way overkill. But, if they were able to sustain higher sequential read IO then it might be worth the extra $1100 per cage. I'm mainly trying to serve the large reporting queries that come through a few times per hour. The rest of the time the CPU and disks sit idle.
  4. joechang New Member

    drive capacity and performance completely separate topics
    there is no substitute for multiple IO adapters/channels and disk drives
    preferable 60+ drives for a good 2 socket system

    for any given disk drive generation & speed,
    capacity differences: ie, 73 & 146 GB
    are creates with platters inside the disk drive
    so the 73G has 1 platter, the 146 has 2

    there are no differences in performance characteristics
  5. egmiii New Member


    Thank you very much! I'm glad to know capacity does not dictate the speed.

    I'm going to purchase an ML370 G5
    1 x 2.66 Quad core chip
    8GB Ram
    P400 /512 for 8 internal drives (OS, Backup, Log)
    E500 /256 for MSA 50 with 10, 72GB 10k drives. RAID 10 for data
    Maybe a 2nd MSA 50 for the other port on the E500, same as above. Is this a problem with regards to card/bus saturation.

    Does anything above seem out of alignment? Too much DISK IO, too much CPU, too little RAM, etc.

    Our DB is 80GB. Very little concurrency. Mostly for 20 people that generate a few reports per day.

    Thanks for your expertise.
  6. joechang New Member

    you might consider something like:
    2 drives for OS, 2 for logs in the first internal 8-bay
    8 drives for data in second internal bay,

    8-10 drives in MSA 50 for data
    or a second MSA 50 in lieu of the 8 internal drives
    or 8 internal + 2 MSA50

    no reason not get 3+ controllers, they are realatively inexpensive compared to the storage chassis + disks

    I prefer to carve the data drive/arrays into 3 partitions
    1. for data files
    2. for tempdb data
    3. for backup

    also, consider buying the second 2.66GHz proc anyways,
    even if your initial license is for 1 SQL Server socket
    then if you decide you need more power, the processor is already there
  7. alexboy456 New Member

    Howabout going for the 15k rpm disks in the server?
  8. mcosy New Member

    Hi JO,

    If we have 8 cores, do we need to have 8 temp data files. if so how do we place?
  9. joechang New Member

    according to MS, if your app makes extensive use of temp tables, or other use of the tempdb, which could be queries with worktable, ie, hash, sort, and other intermediate results

    it could generate a lot of writes to the tempdb system tables
    in which case, multiple tempdb data files are preferred

    however, it was never clearly explained as to whether it actually helps to create multiple files to the same disks

    so, if you configured your system for adequate storage performance,
    ie, 2-4 controllers, 2-4 racks of external storage
    you will probably have 4-8 arrays any ways.
    in which, place one tempdb data file on each array, same with data

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