Intel Rapid Storage RAID 5 question

[mxnerd]

I now have 4 500G drives and I want to create a RAID 5 array.

My motherboard is Z68 based and got six SATA ports.

Let's assume 0 & 1 is for SSD without raid, and I want put these 4 drives on port 2-5.

And they are drives A, B, C, D on port 2, 3, 4, 5 separately when the array is created.

If somehow later on I pull the drives out but forgot which port each drive corresponds to and messed up and put them back like drives C, B, A, D correspond to port 2, 3, 4, 5.

Will this destroy the array or it does not matter?

Thanks!!!

 

[Emulex]

doesn't matter it marks the drives even if they don't have a wwn.

Real raid keeps a copy of the wwn and stamps the drives to be double dog sure but ich the last time i used it did fine with moving.

btw you are setting yourself up for epic fail raid-5. why not spend $50-100 bucks on a real raid controller with BBU and definitely use RE3/RE4 drives?

Raid-5 is not acceptable to anyone (definitely not sys-admins). raid-10 or raid-6 equivalent.

I'd go with a cheap LSI controller, TLER compliant drives and raid-10 if you asked me.

or JBOD.

Raid-5 on intel ich is e-peen stuff. Wait for it to burn down 😉

 

[mxnerd]

Thanks.

I tested myself and it works. The port does not matter.

I know Intel RAID is rubbish so it's only temporary solution. It's for my personal use. I'll buy a LSI controller in a few weeks.

 

[mxnerd]

I know Intel Raid is rubbish, but how can Intel Raid 5 write perforamce this bad?

These are 4 Seagate 2.5" 7200RPM 500GB 2.5" drives

Did I do something wrong?

 

[Goros]

Just buy a used M1015 flashed to an LSI9220, 9240, or 9211 based on your needs. Should run under $120 shipped.

 

[mxnerd]

I will buy a true RAID controller ASAP. I created this RAID 5 simply for transfer files for temporary storage purpose.

I just can't imagine why the performance of Intel RAID 5 is such, such bad, probably even a lot worse than Windows software RAID?

 

[imagoon]

What you are seeing there is the RAID5 write penalty, most likely very much made worse via the Intel driver using the CPU to do the XOR calculations. RAID5 (and 6 / 50 / 60) have write penalties because the CPU has to do all the XOR work on write. Controllers with XOR engines on the chip and real BBU backed cache can minimize but never eliminate this issue. The writes also in this case likely cause 4x the data to go down the PCIe bus (one for each drive) and typically needs to wait for a sucessful write response from the drive. Worse issues if you are writing smaller chunks of data than the strip set size.

 

[sub.mesa]

It's exactly as it should be. Try enabling volume write-back in the Intel drivers and try again. Please note that onboard and hardware RAID5 are inherently unsafe. You must use a full backup to protect your data. If you depend on the legacy RAID5 to protect your data, there is a good chance you will lose it all.

Swapping disk cabling will work; for now. If later you have a broken RAID array, it could severely cause problems if you want to re-create the array. With disks connected to different ports, the second time you create the array will be created with different layout. The subsequent rebuild will destroy your data - permanently.

Another question: do the harddrives support TLER?

 

[mxnerd]

Another question: do the harddrives support TLER?

I guess not. These are standard SATA drives, not enterprise grade.

Thanks the advices from all . I'll move the data to another drive yet again and purchase a true RAID card ASAP.

Best,

 

[mxnerd]

Just ordered a RAID card from eBay, should arrive in a few days.

Anyway, just for experiment, I tried to enable write back cache on the raid 5 array, but Intel Rapid Storage UI won't let me. I have disabled the Windows write caching from Windows Disk management, disk properties, policy according to Intel Rapid Storage help file.

I'm not writing back any files back to this array now. It's read only. I'm not risking any existing data.

 

[mxnerd]

Shoot! Everyone here is correct. I just lost the array!

Fortunately I still have my backup!

The Intel RAID is really trash!!!

Why the hell INTEL provides on board RAID if it's completely useless??? Why no one sues Intel over data loss if it sucks big time?

 

[mxnerd]

Could have been power supply. Heard some squeaking sound that seems not enough power into the array.

Rearranged the power connectors and the array is back.

But that is scary!

Enough with Intel on board RAID.

 

[Cerb]

If the PSU is an issue, a real controller won't fix that. For 4 SATA drives to stump your PSU, your PSU is not sufficient for booting your computer in that configuration.

RAID 5 is basically on life support, is always a recipe for problems with non-RAID drives, and is usually a recipe for problems even with such drives. This is true regardless of who's controller you have.

Intel RAID is not substitute for LSI or the like, but your problems don't seem to be originating from Intel's RAID implementation, except for the initial performance. You will have similar issues with any other implementation. Just say no to RAID 5, going forward.

 

[mxnerd]

If the PSU is an issue, a real controller won't fix that.

Just say no to RAID 5, going forward.

Thanks. The temporary power lost could be caused by loose Molex Y splitter.

After this, I will either go with RAID 10 or no RAID at all. Actually I never had any confidence in RAID setup in the past. I would rather doing folder mirroring for backup. Fast speed and no down-time is not a necessity for my personal use.

 

[Cerb]

That's pretty common. Servers, which usually get RAID, have little to no hardware changes over their lifespans, are usually also backed up, and usually have semi-paranoid admins watching over them. Sometimes, you want or need desktop RAID, but it's very often a pain, in the long run.