I have fallowing configuration for my SQL 2014 server:

  • SSD RAID 1 - for data files
  • SSD RAID 1 - for tempdb? logfiles?
  • HDD (SAS 15K) RAID 1 - for tempdb? logfiles?

I noticed that sql uses tempdb quite heavly and I wonder how shall I place the logfiles and tempdb to optimize the throughput (the application is not very write intensive). Does it make sense to put logfiles and tempdb on the same SSD array or I should better use the HDD array for logfiles?

  • Retagged your question: SQL is a language, not a DBMS. – Colin 't Hart Aug 11 '14 at 12:26
  • What's the target performance you are looking? How much data you got? Describe the server and disk config a bit more. – vonPryz Aug 11 '14 at 12:38
  • What is your strategy for SSD failure? How badly hurt would you be if you lost the log files due to an SSD failure? Other than cost, why not use RAID 10 for higher protection of your HDD arays? – RLF Aug 11 '14 at 17:26
  • The datafiles have ca. 160GB, logfiles 5GB (1% used). Strategy for SSD failure is RAID1 and stand by server with mirroring. I can only use 8 disks (2 for OS) so RAID 10 is not an option, unless instead of 2xRAID1 I'll use RAID10 with SSDs + RAID1 with HDD and put data file + tempdb + logfiles on RAID10. Does it make sense? – Patryk Aug 12 '14 at 13:18

I have posts on this same subject, but for MySQL and PostgreSQL

I hope my old posts give you insight into doing this for SQL Server


RAID 1 is less suitable for any of Data file, log file and tempdb file. Although RAID 1 provides redundancy by mirroring and also provides bit of a fault tolerance it is kind of outdated with arrival of RAID 5 and RAID10(or RAID1+0). Best is to keep data, log and tempdb on differnt physical drives which are configured either in RAID 5 or RAID10. RAID 10 is more preffered but is costly as compared to other RAID technologies.

If you have restriction with RAID 1 you can use it but then make sure you separate data,log and tempdb files on different physical drive to avoid I/O contention.

Above suggesstion were given because you asked about seggregating files. In many environment because I/O load is relatively less data and log files are kept on same drive, even tempdb is placed on same drive where other files are present. According to surrounding/env/load we can seggregate files to get optimum performance.

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