Forum Discussion
Disk size considerations
Hi Alex, It depends on Storage design. If you can describe what you have in terms of Storage I can help you with the desing.
Let me know the storage model, disks number and LUN + RAID used.
Based on this information I can give recomendations. I helped Dell sales to design storage for SQL and Hyper-V for many years.
Regards
Thanks Lucas. At the moment customer asks if there are any requirements/recommendations from the SQL/SharePoint side. When it comes to storage design, customer has another contractor that will prepare their suggestions. Probably they will base their suggestions on LUN/RAID, etc. that you mention.
Do you know of any recommendation to give from "software" side?
@Александр Сапожков wrote:Thanks Lucas. At the moment customer asks if there are any requirements/recommendations from the SQL/SharePoint side. When it comes to storage design, customer has another contractor that will prepare their suggestions. Probably they will base their suggestions on LUN/RAID, etc. that you mention.
Do you know of any recommendation to give from "software" side?
Good day,
This is a clasic case study mistake which a lot of complanies do
I see this wrong procedure in a lot where companies, get advice from "DBA expert" who prepares the database server, while ignoring other aspects of the system, like the storage design or the applications, which actually use the database, and latter on they take "application expert" and they probably take "storage expert" as well, and each consultant gives opposite advices, while ignoring the other aspects of the system!
A system should always we examine "as a whole" and not in parts!
Advice that fit one system can be wrong to another system even if spesific part (for example SQL/SharePoint configuration) is the same.
Now lety's go back to the original question and give you the short answer that It depends on Storage design and much more :-)
There is no way to give advice based on the information we have here. The only thing I can give you are "golden rules" and comments, which should help you or your experts to get the right decission.
>> Splitting the data should be first of all a matter of performance usually. Using single file usually in most cases (smaller DB as well) reduce performance, as SQL Server is a multi task application.
>> The question should not focus only on the size of the files but ion the storage desighn, how you splite the data between these files, and how/where you store the files...
>> In general in most cases, I recommend to split the data to files according to the way you use the data and store the data. The idea is to split the data across disk to balance the use and get better performance.
>> In general in most big databases I recommend to split the file to 6TB or less each. 16 TB is big but not huge and spliting to 4TB size make sense in first glance. Using 16TB single file is something I probably will not advice you to do. You should think about mainanence as well as "the way you use the data and store the data" which I mentioned above. The number 6TB related to several parameters including the size of backup tapes (like HP C7976A LTO 6 ) which are common in use.
Your question was only about the size of the file while you should think about the way SQL Server work regarding the data and the memeory and the entire system around it. I highly recommend to search the web for "best practice" articles and cases. In the mean time, I hope these short comments could help you and point you to the right way :-)
I like RA's comments.
When we consider the storage specifications, we do have to think it as a 'whole thing' and not just parts. In my experiences, the things below are what I want to share:
Hardware aspect
1. Are you going to install only one database instance onto physical server? Or VM or Hyper-V will be implemented which mean you may have multuple server files and database files on disks?
2. Would you like to apply RAID to share the risky of hardware damage? If yes, which RAID level would would you like to apply? because different level requires different physical disk arrangement.
DBA aspect
1. How many databases will you have in one database server? Because each database at least contains 2 files sucj as *.mdf and *.ldf. If you have n databases in one server and all databases grow rapidly, then you must consider to split them on different servers which means you need big storage disk spaces.
2. For the historical data, how long will be kept in databases? In my nation, the goverment says the transactions shall be kept at least 2 years. What is yours?
3. As we know, SQL server supports the file group that means the data can be stored into specific logical file against the critiria we set in the database storage setting. For example, the transactions which occured in 2007 are in the fg2007.ndf; transactions in 2008 are in fg2008.ndf....etc.
4. What is your backup plan? Are you going to backup all databases or specific database? How often? Please be aware that back up a huge file always takes much time than backup several small files.
5. Don't forget the indexes and statistical data are including in the database.
Additional aspects
What kinds of source will be stored into database? such as Videos, iamges...or just text only?
All those things above will reflect the disk size specifivcation you make. I know what I list above are not covered all considerations but I just intend to prove what RA said.
Hope it's useful for you!!!!
