jwcolby
jwcolby at colbyconsulting.com
Sat Jun 13 18:52:04 CDT 2009
Steve, This is for 4g dimms. I have 8 gigs in my servers right now but that is (4) sticks of 2 gigs each. I am now going to replace that with (4) sticks of 4 gigs each. I run SQL Server on these machines and I have largish databases, about 180 gig database files, 50 million records, 640 fields wide. I have to do cover indexes on up to 14 or more fields at a time to get my speeds up to snuff. If I can get twice the memory it should help with the processing speed a bit. My next move is to place these databases on a raid of solid state disks, probably a raid (5) using three (to start) of these: http://www.newegg.com/Product/Product.aspx?Item=N82E16820227395 This is a review of the drive comparing it to other drives, both SSDs as well as normal hard drives. http://benchmarkreviews.com/index.php?option=com_content&task=view&id=299&Itemid=60 Perhaps of most interest to me are these three tests which show read/write speeds (I rarely write to my drives except for generating cover indexes) as well as IOPS. Access times: http://benchmarkreviews.com/index.php?option=com_content&task=view&id=299&Itemid=60&limit=1&limitstart=5 Read / write speeds: http://benchmarkreviews.com/index.php?option=com_content&task=view&id=299&Itemid=60&limit=1&limitstart=5 IOPS: http://benchmarkreviews.com/index.php?option=com_content&task=view&id=299&Itemid=60&limit=1&limitstart=8 My databases are the exception in that they are almost entirely read only. This will provide an advantage in that I will not be wearing out the SSDs writing to them all of the time, and for a database, the scorching read data rates and the truly scorching IOPS rate MIGHT provide truly scorching query processing rates. And to top it off, SSDs to not suffer from the effects of disk fragmentation - reads to any location are equally fast. Basically I set up this "database from hell" which is the very wide table on a raid 6 array of normal hard drives. However I do not USE that database directly. I set up cover indexes, many of which are static, they cover the most common fields that are used over and over from order to order. I then (very occasionally now) have to generate cover indexes for specific sets of fields from that big wide table. If I can set JUST those cover indexes into database files out on a raid 5 array of these SSDs I should get just phenomenal performance. Given disk access times of 100 microseconds, a raid sustained data transfer rate of as much as 500 mbytes / second, and even more if I add more disks to the raid array, and IOPS of many thousands per second, it would SEEM that even large queries should simply fly. Talk about keeping the processor fed... We shall see. John W. Colby www.ColbyConsulting.com Steve Erbach wrote: > John, > > I had to check what my memory was: CPUZ tells me that my 8GB of RAM > (2GB PC2-6400 sticks) is 400 MHz. This system is about a > year-and-a-half old. > > Steve Erbach > Neenah, WI