June 26, 2012 at 8:42 am
My concern with one big RAID10 is again "survivability". If you do somehow lose the (4-drive) RAID 10 here, all the dbs are also lost.
With two RAID1s, you can place files such that even with the loss of a single RAID1, you can recover all the dbs.
Yes, RAID10 failures are very rare, but they still can happen (especially if some external force/action physically damages the drives).
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".
June 26, 2012 at 8:50 am
>>use a windows scheduled task to execute scripts via SQLCMD
Been doing that for a LONG TIME...
SCHTASKS is what you want to use. See here for nice documentation:
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/schtasks.mspx
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
June 26, 2012 at 9:18 am
ScottPletcher (6/26/2012)
If you do somehow lose the (4-drive) RAID 10 here, all the dbs are also lost.
That's why you take backups. You're more likely to lose a complete RAID1 mirror, than you are 3 drives out of a 4 disk RAID10 array
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"Ya can't make an omelette without breaking just a few eggs" 😉
June 26, 2012 at 9:29 am
You're more likely to lose a complete RAID1 mirror, than you are 3 drives out of a 4 disk RAID10 array
OK, but it's not the odds against losing it, it's CAN you recover if you do.
If you have only 4 data drives and RAID 10 them, you had NO other recovery except a backup.
If you have two RAID1 sets, by careful placement, you can recover all databases even if one of the two raid sets fails. You can't recover anything if the RAID10 fails.
That would be my concern -- a complete loss of all databases.
[OP's alreadys stated he doesn't do frequent backups, so I think he wants a system where data can be recovered even after a RAID set failure.]
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".
June 26, 2012 at 9:32 am
ScottPletcher (6/26/2012)
You're more likely to lose a complete RAID1 mirror, than you are 3 drives out of a 4 disk RAID10 array
OK, but it's not the odds against losing it, it's CAN you recover if you do.
If you have only 4 data drives and RAID 10 them, you had NO other recovery except a backup.
If you have two RAID1 sets, by careful placement, you can recover all databases even if one of the two raid sets fails. You can't recover anything if the RAID10 fails.
That would be my concern -- a complete loss of all databases.
[OP's alreadys stated he doesn't do frequent backups, so I think he wants a system where data can be recovered even after a RAID set failure.]
RAID (any form) is no replacement for backups. Anyone who thinks so is planning to fail instead of planning for a failure.
June 26, 2012 at 12:56 pm
ScottPletcher (6/26/2012)
You're more likely to lose a complete RAID1 mirror, than you are 3 drives out of a 4 disk RAID10 array
OK, but it's not the odds against losing it, it's CAN you recover if you do.
If you have only 4 data drives and RAID 10 them, you had NO other recovery except a backup.
If you have two RAID1 sets, by careful placement, you can recover all databases even if one of the two raid sets fails. You can't recover anything if the RAID10 fails.
That would be my concern -- a complete loss of all databases.
[OP's alreadys stated he doesn't do frequent backups, so I think he wants a system where data can be recovered even after a RAID set failure.]
1) You REALLY need to give this line you are pursuing up Scott. I (and others it seems) strongly believe you are fighting a battle you cannot win and which also doesn't help anyone.
2) I only had about 5 hours of sleep in the last 55 hours so I can't for the life of me figure out what you mean that by placement of file groups you can avoid the loss of any database if one of two RAID1 sets fails completely. Please take a DISK1 and a DISK2 (both RAID1s) and a DB_A and a DB_B and give me something I can visualize to understand what you mean. Please include the tlog files as well as any file groups you need.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
June 26, 2012 at 1:33 pm
TheSQLGuru (6/26/2012)
ScottPletcher (6/26/2012)
You're more likely to lose a complete RAID1 mirror, than you are 3 drives out of a 4 disk RAID10 array
OK, but it's not the odds against losing it, it's CAN you recover if you do.
If you have only 4 data drives and RAID 10 them, you had NO other recovery except a backup.
If you have two RAID1 sets, by careful placement, you can recover all databases even if one of the two raid sets fails. You can't recover anything if the RAID10 fails.
That would be my concern -- a complete loss of all databases.
[OP's alreadys stated he doesn't do frequent backups, so I think he wants a system where data can be recovered even after a RAID set failure.]
1) You REALLY need to give this line you are pursuing up Scott. I (and others it seems) strongly believe you are fighting a battle you cannot win and which also doesn't help anyone.
2) I only had about 5 hours of sleep in the last 55 hours so I can't for the life of me figure out what you mean that by placement of file groups you can avoid the loss of any database if one of two RAID1 sets fails completely. Please take a DISK1 and a DISK2 (both RAID1s) and a DB_A and a DB_B and give me something I can visualize to understand what you mean. Please include the tlog files as well as any file groups you need.
I agree, I need a visual. Anything I draw up, I lose at least one database if I lose both disks in a Raid 1 configuration.
June 26, 2012 at 1:35 pm
Lynn Pettis (6/26/2012)
RAID (any form) is no replacement for backups. Anyone who thinks so is planning to fail instead of planning for a failure.
I concur
To add to Kevins comment, a RAID10 array will inherently offer better performance and redundancy, by design!
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"Ya can't make an omelette without breaking just a few eggs" 😉
June 26, 2012 at 2:10 pm
You lose the db as it exists if a RAID1 fails, but if you place the files properly on the two RAID1s, the db can be fully recovered, which would not be the case for a RAID10 on which all the files were placed.
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".
June 26, 2012 at 2:13 pm
ScottPletcher (6/26/2012)
You lose the db as it exists if a RAID1 fails, but if you place the files properly on the two RAID1s, the db can be fully recovered, which would not be the case for a RAID10 on which all the files were placed.
Pretend we are from Missouri and show us.
June 26, 2012 at 2:35 pm
Lynn Pettis (6/26/2012)
ScottPletcher (6/26/2012)
You lose the db as it exists if a RAID1 fails, but if you place the files properly on the two RAID1s, the db can be fully recovered, which would not be the case for a RAID10 on which all the files were placed.Pretend we are from Missouri and show us.
Missouri would be a nice step up for me - I live (although thankfully am not FROM) in Alabama!! :hehe:
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
June 26, 2012 at 2:43 pm
ScottPletcher (6/26/2012)
You lose the db as it exists if a RAID1 fails, but if you place the files properly on the two RAID1s, the db can be fully recovered, which would not be the case for a RAID10 on which all the files were placed.
Going out on a limb here...lots of heavyweights on this thread.
As I understand it having database files stored across two arrays (data on one array, logs on the other) gives us a better chance of recovering to the point immediately before an array failure than having the files on only one array. If we lose the array containing the data files but the log file array is OK we have a chance. In either scenario however (one array or two) if we lose an array I think we still need to be in full recovery mode and have valid backups to have a chance of recovering data, which is not the scenario here.
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato
June 26, 2012 at 2:58 pm
TheSQLGuru (6/26/2012)
Lynn Pettis (6/26/2012)
ScottPletcher (6/26/2012)
You lose the db as it exists if a RAID1 fails, but if you place the files properly on the two RAID1s, the db can be fully recovered, which would not be the case for a RAID10 on which all the files were placed.Pretend we are from Missouri and show us.
Missouri would be a nice step up for me - I live (although thankfully am not FROM) in Alabama!! :hehe:
Born, raised, and live in Colorado.
June 26, 2012 at 3:27 pm
opc.three (6/26/2012)
ScottPletcher (6/26/2012)
You lose the db as it exists if a RAID1 fails, but if you place the files properly on the two RAID1s, the db can be fully recovered, which would not be the case for a RAID10 on which all the files were placed.Going out on a limb here...lots of heavyweights on this thread.
As I understand it having database files stored across two arrays (data on one array, logs on the other) gives us a better chance of recovering to the point immediately before an array failure than having the files on only one array. If we lose the array containing the data files but the log file array is OK we have a chance. In either scenario however (one array or two) if we lose an array I think we still need to be in full recovery mode and have valid backups to have a chance of recovering data, which is not the scenario here.
Everything you said makes sense and rings true to my tired brain.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
June 26, 2012 at 3:48 pm
I'm NOT relying on RAID to replace backups. I do backup regularly, just manually and not every day - sometimes days go by with no new data. I'd like to put in some sort of test, when I automate the routines, so I don't make completely unnecessary backups. Seems like one of the partial backups would be appropriate here, so I don't make lots of copies of unchanged data.
And I don't have a clear picture of how to automate naming and storage of cascading backups. So far I've just been doing full backups, compressing them and renaming them manually to the current date, then storing them on another computer. It works, but it's clunky and I have to do it myself. Still lots of studying ahead of me, to get a clean and functional system set up for this task.
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