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RAID 6 or RAID 10 for CAD files on an array of 48x 10K disks Equallogic NAS FS7610
Up to 125 users (when other architects from other firms are working here on bigger projects) can have to work on CAD files (Autocad 2013 / 2014) Every user will open about 5 to 10 CAD files. Each autocad file will then open up to 15 xref files. Several other files (DWL, DWL2) are updated (saved) on a regular basis. The autosave is set to 5 or 10 minutes.
Meanwhile the users are working with Office, PDF and the list goes on.
Up to 20 users are working on 3D softwares (files are kept on the network)
We started to use Revit. In 3 to 5 years we'll see more projects on Revit than Autocad. But we currently use Autocad.
QUESTION: Dell has recommended to set a pool in RAID 6 instead of RAID 10 on our two Equallogic PS6110. The Equallogic FS7610 is amazingly fast. But we've been using file servers connected to SAN in RAID 10 for years.
They told me that the number of drives (48x 10K SAS drives) could slighly increase the performance. But RAID 6 is not a RAID level I,ve been working with before. I don't see how RANDOM WRITE can be faster no matter the number of drives we have.
It's less a problem for 3D or Revit. Files are larger. But I'm a little concern about Autocad.
Any advice is welcomed
Thanks
Meanwhile the users are working with Office, PDF and the list goes on.
Up to 20 users are working on 3D softwares (files are kept on the network)
We started to use Revit. In 3 to 5 years we'll see more projects on Revit than Autocad. But we currently use Autocad.
QUESTION: Dell has recommended to set a pool in RAID 6 instead of RAID 10 on our two Equallogic PS6110. The Equallogic FS7610 is amazingly fast. But we've been using file servers connected to SAN in RAID 10 for years.
They told me that the number of drives (48x 10K SAS drives) could slighly increase the performance. But RAID 6 is not a RAID level I,ve been working with before. I don't see how RANDOM WRITE can be faster no matter the number of drives we have.
It's less a problem for 3D or Revit. Files are larger. But I'm a little concern about Autocad.
Any advice is welcomed
Thanks
ASKER
I'm sorry I misleaded you. Almost all files are smaller files (CAD files) RAID 6 is known to offer the worse performance in random write.
Actually RAID10 does not let you lose 2 disks, heck, it can't always protect on a single HDD failure. Example, you have a 4-disk RAID10, where disk A&B are one mirror & disk C&D are the other.
Lets' say disk #B has a bad (unreadable block), which is quite to be expected. Now disk #A fails. This guarantees at least partial data loss. If that bad block happens to contain part of the registry, or boot block, or a SQL database, then you could end up with a lot of lost data. As RAID controllers typically do chunks of 64KB, you end up with not one bad block, but 64KB or more of lost data also. (and if it is a 6-drive RAID10, then that 64KB typically becomes 64KBx3, and so on ...) This could affect hundreds of files depending on how things are arranged.
Use RAID6 & sleep at night. You'll still have to archive offsite to protect against natural disasters and human error, but at least you won't be sweating during a rebuild.
Lets' say disk #B has a bad (unreadable block), which is quite to be expected. Now disk #A fails. This guarantees at least partial data loss. If that bad block happens to contain part of the registry, or boot block, or a SQL database, then you could end up with a lot of lost data. As RAID controllers typically do chunks of 64KB, you end up with not one bad block, but 64KB or more of lost data also. (and if it is a 6-drive RAID10, then that 64KB typically becomes 64KBx3, and so on ...) This could affect hundreds of files depending on how things are arranged.
Use RAID6 & sleep at night. You'll still have to archive offsite to protect against natural disasters and human error, but at least you won't be sweating during a rebuild.
ASKER
Thanks again
But I already know how safe RAID 6 is. We have 48 disks. My concern is that I can put myself in a situation where I'll have to switch from RAID 6 to RAID 10 in the event that it's not fats enough: cad files will be saved massively.
I'd prefer to keep RAID 6. But on the Equallogic we can switch from raid 10 to raid 6 but not the other way around.
But I already know how safe RAID 6 is. We have 48 disks. My concern is that I can put myself in a situation where I'll have to switch from RAID 6 to RAID 10 in the event that it's not fats enough: cad files will be saved massively.
I'd prefer to keep RAID 6. But on the Equallogic we can switch from raid 10 to raid 6 but not the other way around.
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This is a scenario I was thinking about. But I'd prefer to have one big pool, same RAID to keep it simple. But you're right RAID 10 is not as safe as RAID 10. But RAID 10 with two spare is not that bad too.
The engineers in Canada love free "everything" (to see why Google commission Charbonneau engineer) Fortunately most of the time I'm dealing with architects.
So RAID 6 being very slow on random write is something you agree on, no matter the number of disks?
Thanks again
The engineers in Canada love free "everything" (to see why Google commission Charbonneau engineer) Fortunately most of the time I'm dealing with architects.
So RAID 6 being very slow on random write is something you agree on, no matter the number of disks?
Thanks again
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RAID10 with spares are NO safer than RAID10 without spares. You aren't safe while you are degraded. The only thing the spare does is minimize the time before a rebuild starts.
But as a professional storage architect who designs RAID subsystems and writes diagnostic code, I'll give you another $0.02 to consider .... If the data is valuable then you do NOT want to automate a rebuild. That is profoundly stressful on the surviving disks.
The smartest thing to do is kick off a backup of your most important files BEFORE you begin the rebuild. In RAID10 you have no parachute, no room for error once you are degraded. Does it not stand to reason that is is more important to create a current backup first?
And creating one large target is just nuts. It places all your eggs in the same proverbial basket. You won't have any flexibility to reconfigure anything at the LUN level, or even do filesystem or chunk size related tuning.
But as a professional storage architect who designs RAID subsystems and writes diagnostic code, I'll give you another $0.02 to consider .... If the data is valuable then you do NOT want to automate a rebuild. That is profoundly stressful on the surviving disks.
The smartest thing to do is kick off a backup of your most important files BEFORE you begin the rebuild. In RAID10 you have no parachute, no room for error once you are degraded. Does it not stand to reason that is is more important to create a current backup first?
And creating one large target is just nuts. It places all your eggs in the same proverbial basket. You won't have any flexibility to reconfigure anything at the LUN level, or even do filesystem or chunk size related tuning.
ASKER
Thanks for the article and all the advices. The "best practice and guidlines..." you were refering to is the one I was reading yesterday. But I'm not sure how to set volume access to block instead of files in the Equallogic. I'm well aware of the backup. All files - as well as the VMs - are backed up into a barracuda backup that is sending it out into the cloud.
I want to make sure the raid level I'm selecting is not going to slowing it down. The number of pools will not really (but I'm not an expert) increase the writing, it's 2 IO in RAID 10 against 6 IO in RAID 6
I feel safer with RAID 6. But don't you think RAID 10 is more appropriate for CAD files?
Thank again, it's very helpful.
I want to make sure the raid level I'm selecting is not going to slowing it down. The number of pools will not really (but I'm not an expert) increase the writing, it's 2 IO in RAID 10 against 6 IO in RAID 6
I feel safer with RAID 6. But don't you think RAID 10 is more appropriate for CAD files?
Thank again, it's very helpful.
I very much doubt that you will notice the difference between raid 10 and raid 6 and you will be able to sleep at night and not worrying about the drive that is going to fail.. they all do some within 30 days some not for years of hard use. If you have to just add more storage to your battery backed up cache.
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Can you have RAID 60 on that box though? As far as I understand only RAID levels 6, 10 and 50 are available. There are two storage boxes anyway and presumably he important data will be mirrored on both so UREs aren't as important as they would be on a single box, total array failure is what is going to cause any problems.
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Thanks everyone !
~conlly33