I have a question about raid. I currently have software raid setup on my servers and want to know if i get a card raid can i change the raid without starting all over again or no? And also is Raid 5 good? What raid do you recomment that is the best and keeps data safe? Let me know thanks!
I cannot answer your first question. However, simple raid1 is good enough to keep data safe. However, raid10 will give you more read-write ressource (called i/o) so in intense server applications, it is best. Raid 5 is slower for both read and write as it as to write a parity bit or skip to read it. In both case, a battery can be added a to an hardware raid card, so in case of power failure, cache will keep the data and finish wroting it when power returns. this is for very critical data protection.
First off, what is the purpose of the computer/server (database, personal, web host, etc...)? As to the first question. This is generally possible, provided that you don't have to use the same drives for the hardware raid. You basically set up a raid array on the card, boot the OS like normal, and use Ghost or Acronis or another imaging program to copy the old hard drive to the new array. Acronis is the best way to do this that I've found. There's several steps that need to fall in place in the correct order for this to work properly, but it is usually possible. As for the RAID 5, it depends on what you are using the RAID for.
Hey got a few servers, one is database which is currently using raid1 and want to switch it to raid5 the other is for webhost let me know thanks!
For the DB you want to go with RAID 10 if at all possible. RAID 5 is not an ideal match for a DB because the controller takes extra time to calculate and write the parity bit. If this is software RAID it comes at the expense of the OS. Good hardware cards can make this manageable, but it's not near as fast as 10. The parity bit isn't a problem with RAID 10. Both RAID 5 and 10 have good read performance. If you have read heavy database usage, 5 may work, but it is much slower than 10 for writes. RAID 5 should be fine for a web server. Again, a hardware card is much better than software RAID. In any case, the more drives the better.
Hey thanks for the info. Just one last question is though raid 10 lets you use less of the total hard drive space then raid 5, is there maybe another raid that gives you speed + alot of storage space?
RAID 5 is probably the best combination. RAID 10 is 50% efficient for storage space, RAID 5 is (n-1)/n efficient.
RAID 5 is great! Yes it takes more drives and you wont get as much space as say a RAID 0 or 1... BUT if you have a drive fail you can swap it out and everythings back to normal. Or so you don't have money for a extra HDD right now. Just leave it and it's still stable and when you can get the HDD! It's awesome!
RAID 1 is the same as RAID 10 for storage efficiency 50%. So, RAID 5 is more efficient (min 66%), but does require at least 3 disks.
For your DB performance, if you can go with RAID10, then do it. RAID10 in most cases will perform better than RAID5, comes with sacrifice in space.