Sql-server – SQL server after RAID problems

For a 4 bay configuration with a high insert/update workload I would go with one of these:

1) Spindle only

• One RAID1 for the log. Back this up with a a few hundred MB of write cache
• One RAID1 for the data files and tempdb

Rationale: you will mostly be writing to the log. Latency of log is king for OLTP and it doesn't get much better than a RAID1 with a write cache. You can use SATA - which should give you at least 80MB/sec sequential writes at latency less than 1ms.

2) SSD plus spindle

• One RAID1 for log with same configuration as the above.
• One RAID1 for data files and tempdb

Rationale: This config will favour higher tempdb load and would be good if you are skimping on DRAM (as this will cause checkpoint activity to go up and drive read I/O)

3) Pure SSD

• Put them in a RAID5 if you are not worried about wearing them out.
• If you are using consumer grade SSD - put them in a RAID10.

Rationale: RAID5 with 4 x SSD is fast enough for nearly all purposes.

Everything goes on same LUN

4) 8 bay, spindle only config

• Put 2 disks in RAID1 for the log file.
• Rest goes into a RAID10 or RAID5 (RAID10 if you are worried about tempdb)

Overall: always prefer a 2 spindle RAID1 with a write cache for logs. It's plenty for 99% of all cases (80MB/sec for SATA and up to 120MB/sec for SAS).

Please ask them and also, as max pointed out, test whether such tool can provide point in time recovery. Test various scenarios and see if it matches your RPO and RTO. I am sure its not free of cost only go if it REALLY provides some thing more than what native SQL Server Tsql backup provides. I have not found any tool more reliable than TSQL built in code for backup.

Ask them,if possible, to do a POC (proof of concept) and show you how it would be better than native TSQL backup. You have to let them know that there is no point in choosing any thing blindly if it does same work as a tool which you have free( inbuilt). You can professionally ask them above questions. Plus if you use such tool you might need to hire a person who is expert in this tool so might be some more extra cost.

Think all pros an cons and then move