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New to RAID 0 and SSD

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March 29, 2010 3:22:47 PM

Hi all.

First of all. Thank you all for all the help you have provided me with the last couple of years. Now i created an account aswell.

My question is, I've bought 2 Intel X25 G2 80GB SSD and will setup a RAID 0 when coming home. One of them is already installed as my system drive with Windows 7 installed and in AHCI mode. Works like a charm.
Now i bought another identical drive and will set it up as a RAID 0 this week.
I've searched the forum for advice and learned a lot.
I wonder if I have to reinstall Windows 7 when doing this RAID 0 setup, or, if I just can do the setup in BIOS, and then configure it with Intel's new drivers/software that arrived the other day? Intel SSD Toolbox or if it was Matrix Storage Manager, dont know the difference really.
Or do I have to reinstall Windows 7 completely?

Thanks in advance

Tim

More about : raid ssd

a c 127 G Storage
March 29, 2010 3:37:06 PM

Intel can migrate from a single disk to a RAID0 array; so if using the Intel controller yes its possible without reinstalling windows.

You would lose TRIM support though, as Intel RAID drivers (even the new ones) cannot use TRIM on a RAID0 array containing SSDs. Only if the SSDs are separate disks on the RAID-controller.

So if you opt for a RAID0 for your two Intel SSDs; i would suggest a reinstall:
- secure erase your current SSD
- setup RAID0 with two SSDs
- insert Windows 7 setup dvd
- let it find RAID array (has internal drivers already)
- create one big partition, leaving ~20GB unused.

So while you lose the 20GB capacity; you would not need TRIM support in this case. You might want to consider this setup instead, as it would give you more performance and prevent strong performance degradation over time.
March 29, 2010 4:01:51 PM

sub mesa said:
Intel can migrate from a single disk to a RAID0 array; so if using the Intel controller yes its possible without reinstalling windows.

You would lose TRIM support though, as Intel RAID drivers (even the new ones) cannot use TRIM on a RAID0 array containing SSDs. Only if the SSDs are separate disks on the RAID-controller.

So if you opt for a RAID0 for your two Intel SSDs; i would suggest a reinstall:
- secure erase your current SSD
- setup RAID0 with two SSDs
- insert Windows 7 setup dvd
- let it find RAID array (has internal drivers already)
- create one big partition, leaving ~20GB unused.

So while you lose the 20GB capacity; you would not need TRIM support in this case. You might want to consider this setup instead, as it would give you more performance and prevent strong performance degradation over time.


Great info. Thank You. I will do as You say.
2 more questions.

1. What about the leaving 20GB of unallocated space?
2. I was reading on another forum that, quote "9.6.0.1014 version of the Intel’s Rapid Storage Technology driver now enables TRIM for every SSD in the RAID array, across all volume types except RAID 5." end quote.

Related resources
a c 127 G Storage
March 29, 2010 9:17:34 PM

1. Leaving space unused will make it available for the SSD to use internally. Intel SSDs already have internal space reserved for this, about 8% of their capacity (difference between GiB and GB). That might be a little on the low side, so giving it some extra would help protect against performance degradation over time.

Normally, TRIM would do this as it enables the SSD to use free space on your NTFS filesystem/partition, while without SSD after some time of usage the SSD thinks all blocks are in use even though you might have removed alot of data and have plenty of free space.

So either use TRIM and keep ~10GB free on your filesystems - OR - if you can't use TRIM then make a partition smaller than the full capacity, meaning some 10GB remains unused. Since you talk about a RAID0 of two SSDs, i would double that number to 20GB; so 10GB extra reserved space for each SSD.

But you might not need to do this, as you might have been correct about point 2. So if you can indeed use TRIM in a RAID0 of two SSDs, then you may not need the above advice and can create one big partition.

I still recommend you do a secure erase on the SSD you already have, though. A full format under windows 7 would work too, but you lose write cycles which you don't if you use the Secure Erase method. This method involves using a program called HDDerase, which can access the 'protected' HPA areas on the SSD.
March 30, 2010 10:51:31 AM

sub mesa said:
1. Leaving space unused will make it available for the SSD to use internally. Intel SSDs already have internal space reserved for this, about 8% of their capacity (difference between GiB and GB). That might be a little on the low side, so giving it some extra would help protect against performance degradation over time.

Normally, TRIM would do this as it enables the SSD to use free space on your NTFS filesystem/partition, while without SSD after some time of usage the SSD thinks all blocks are in use even though you might have removed alot of data and have plenty of free space.

So either use TRIM and keep ~10GB free on your filesystems - OR - if you can't use TRIM then make a partition smaller than the full capacity, meaning some 10GB remains unused. Since you talk about a RAID0 of two SSDs, i would double that number to 20GB; so 10GB extra reserved space for each SSD.

But you might not need to do this, as you might have been correct about point 2. So if you can indeed use TRIM in a RAID0 of two SSDs, then you may not need the above advice and can create one big partition.

I still recommend you do a secure erase on the SSD you already have, though. A full format under windows 7 would work too, but you lose write cycles which you don't if you use the Secure Erase method. This method involves using a program called HDDerase, which can access the 'protected' HPA areas on the SSD.



Thank You a lot!

Best regards Tim
a b $ Windows 7
a c 167 G Storage
March 30, 2010 3:13:33 PM

You might want to read this recent article from anandtech:
http://www.anandtech.com/show/3618/intel-x25v-in-raid0-...

It will answer many of your questions.

I have used raid-0 with two of the X25-M 80gb gen1 drives. I did it mainly to get a single 160gb image. It performed well enough. I did replace them with a single X25-M 160gb gen2 drive, and AHCI and windows-7 to use trim. My perception is that it works a bit better, but I have not done any tests.

I went from a single drive to the raid configuration by cloning using acronis true image. No problem.
To use trim, you need AHCI(vs ide compatibility). There are other advantages of AHCI too.
Raid-0 includes AHCI as a subset. The problem is that the intel chipset drivers do not pass on the trim commands; only the native Windows-7 drivers do. When that changes, as it inevitably will, then there will be no problem. In the meantime, what to do? The anandtech article which was using the 40gb X25-V drives suggests leaving a bit of your 160gb raid-0 capacity free. Perhaps allocating only 140gb. The intel controllers will recognize the extra space to keep performance up. In time, when all the trim support is there, the reserved space can be released.
March 30, 2010 7:01:00 PM

Great. My issue/question is solved thanks you You.
March 30, 2010 7:12:29 PM

geofelt said:
You might want to read this recent article from anandtech:
http://www.anandtech.com/show/3618/intel-x25v-in-raid0-...

It will answer many of your questions.

I have used raid-0 with two of the X25-M 80gb gen1 drives. I did it mainly to get a single 160gb image. It performed well enough. I did replace them with a single X25-M 160gb gen2 drive, and AHCI and windows-7 to use trim. My perception is that it works a bit better, but I have not done any tests.

I went from a single drive to the raid configuration by cloning using acronis true image. No problem.
To use trim, you need AHCI(vs ide compatibility). There are other advantages of AHCI too.
Raid-0 includes AHCI as a subset. The problem is that the intel chipset drivers do not pass on the trim commands; only the native Windows-7 drivers do. When that changes, as it inevitably will, then there will be no problem. In the meantime, what to do? The anandtech article which was using the 40gb X25-V drives suggests leaving a bit of your 160gb raid-0 capacity free. Perhaps allocating only 140gb. The intel controllers will recognize the extra space to keep performance up. In time, when all the trim support is there, the reserved space can be released.



One last question. Can i do this operation from within windows7/Storage manager regarding that TRIM is not supported in my scenario? Or should I do a total whipe of my 2 SSD and reinstall w7? (back to the first question)
a b $ Windows 7
a c 167 G Storage
March 30, 2010 9:14:12 PM

If you convert a single drive to raid-0 by adding a second drive to the array, I think you need to do a reload. When defining a raid-0 set, one of the choices is what stripe size to select. I did a lot of research, and came to no definitive answer. The stripe size defines how much data is to be grouped together on each drive in an alternating fashion. I picked 64k as a middle of the road size. In order to get this alternating allocation, something has to initialize the drive pair by moving half of the data from the first drive to the second. I think it is possible for the intel raid manager to do this, but I don't know if it does.

If you have a spare hard drive and some cloning program, then clone your 80gb ssd to the temporary hard drive, and boot from it. Then set up both 80gb ssd's as a raid-0 array and clone back to the array. That way, you always have a good system to fall back on if something should go awry.

I think you could also do this by using windows 7 backup to someplace and use the windows-7 install dvd to recover to the newly created raid-0 array.

Unless you can get trim support into the intel raid drivers, don't worry much about not having trim initially. The intel controller is quite good without it. Just don't allocate the full 160gb. Even after windows-7 is loaded, you should be able to use the storage manager to reduce the space allocation to 140gb or so.
!