RAID SSD and SD

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2manydjs

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It seems the internal SSD card has roughly the speed of a class 6 SD card. Would it be possible to run the internal SSD and a 8GB SD card in soft-RAID (0 or 1) to increase speeds?
 
negatory...at least not on this hardware...dont even know if its possible with ssd drives yet period anyways...actual ssd drives are so fast anyways that there prob would be minimal difference...unless of course you are looking for redundancy/data protection...but since this is a netbook then whats the point
 
What would you use that for? Linpus is already near instantaneous, and since the included SSD only has a couple gigs left over after the OS is installed, you wouldn't be able to use it anyway.
 
Running in RAID 0 gives you 16 GB and other OS's could you use the extra throughput.
 
Linpus automatically adds the memory you add in the left SD slot to the main memory, meaning you would already get a theoretical 16 GB. I am waiting for my 8GB SD card that I got on Amazon for $24. I didn't realize Linpus only leaves you ~3 GBs, that's barely enough to install any apps safely!
 
2manydjs said:
The throughput speeds should theoretically double.
Click to expand...

??? !

why should they double?

the access time is allready next to nothing

what you get with a raid0 : (high probability of disk errors with fat32 left asside :) )
+ slow bit of increase

raid 1 would bring you: enhanced read / access and relatively secure data environment...

but: access tim is allready ok and your writing speed will not enhance at all! due to the whole data
beeing written to both disks! you can read faster : but : reading is not the prob with the drive...
 
but like i posted in the windows corner (sry for referring to myself) what you are looking for, could be some kind of "prefetching"

thats what progs like ebooster do: they emulate the "reasy boost" of vista. writing a cache on the different drives to access it easier. like that you def. have a faster access... specialy because mostly the drive is blocked due to writing... then again: the disk reads good: 30-35 mb/s access: 0,2 ms
 
Le Tigre said:
??? !

why should they double?

the access time is allready next to nothing
Click to expand...

Access time is not the subject of the matter and will likely be a bit worse. The throughput (read and write) will (theoretically) double because it has two units to read from or write to. Here is a benchmark of 2, 3 and 4 SSD RAID 0 setups. The setups have been thoroughly tested and the speed improvements are definitely impressive.

PS I'm not interested in using Windows, but thanks for the pointer.
 
Kev50027 said:
Linpus is already near instantaneous.
Click to expand...
Yes but Windows, Ubuntu or Mac OS-X are not so streamlined (+/-1min boot-time). The price to pay for more functionalities and customization...
RAID-0 is definetely a good idea.
(Did you ever hear about gamer-PCs with RAID-0 : 2*Raptors 10,000rpm 70gb HDs as system+games main logical-disk : 140gb available and amazing speeds!) :o

Now how can we do that?
Some options in Disk Utility in MacOS, but the bios is managing it usually (not?) and needs to be RAID compliant?!
 
I found this link to install Ubuntu with software RAID1 (RAID0 should also be available...)
http://www.howtoforge.com/how-to-instal ... ware-raid1

I'll try as soon as I can (+benchmark the new intelSSD+SDHC 8go RAIDdisk and compare with intelSSD alone)...
Ubuntu boot should be faster with it (and every operation) - I am always amazed at all Ubuntu can do!
(also the VMWare tutorials on howtoforge to backup a windows system and run it under VMWare server.)
 
raid the 2 SD slots. perfect for work area, speed is pretty much above the built in ssd.
 
I have tried installing with raid on Xubuntu but I am having no luck so far. After finally working out how to get the alternate iso to boot off usb, it seems there are some drivers missing. During the ncurses based install, my sd card in the "storage expansion" slot is not recognised. This means the partition manager can only see my ssd and usb drive. How can I create a raid disk with my sd card this way? Is there a special install iso that has drivers like pciehp and sdhci on? I would really appreciate any help with this
 
tymchn said:
I have tried installing with raid on Xubuntu but I am having no luck so far. After finally working out how to get the alternate iso to boot off usb, it seems there are some drivers missing. During the ncurses based install, my sd card in the "storage expansion" slot is not recognised. This means the partition manager can only see my ssd and usb drive. How can I create a raid disk with my sd card this way? Is there a special install iso that has drivers like pciehp and sdhci on? I would really appreciate any help with this
Click to expand...

I had a problem installing debian last night. Basically if I just used unetbootin to make a bootable usb key from the main iso image, once it booted the installer would eventually start looking for the files on the cdrom, which there wasn't and it would bomb out.

What did work was using a boot image

Here is the one for the latest version of ubuntu:

http://archive.ubuntu.com/ubuntu/dists/ ... oot.img.gz

Download that then insert your usb key that you are going to use. If it mounts automatically then unmount it. With it unmounted format it to fat16:
sudo mkdosfs -I /dev/sdb
*Warning make sure that /dev/sdb is the location of the usb key or you will format something that you don't want to!*

Then copy the boot image over:
sudo zcat boot.img.gz > /dev/sdb

Now mount it and copy your xubuntu image over:
sudo mount /dev/sdb /mnt
sudo cp xubuntu.iso /mnt/

Also with the latest version of debian unstable and debian testing there was a bug in the installer that would not allow the wired nic module r8169 to load. I had to install old debian etch and then dist upgrade to testing with the great intel ssd, took like an hour to upgrade the 400mb base system (normally takes 10 min on standard computer)! Hopefully ubuntu won't have that problem.
Using the boot image is pretty straight forward, it should work as long as the kernel in the boot image and the iso are the same (or close)

:D

edit: now that I have read your post again it seems your problem might have been different, oh well this is still good info
 
Unfortunately that didn't help, but thanks for trying. It seems that the alternate install iso supports the creation of raid devices, but does not recognise the sdhc card. While the desktop install iso does recognise the sdhc card, but does not support creating raid devices. Is there any way to combine the two? Or possibly create these raid devices another way with the desktop install iso? There doesn't seem to be an advanced mode for the partition manager.
 
tymchn said:
Unfortunately that didn't help, but thanks for trying. It seems that the alternate install iso supports the creation of raid devices, but does not recognise the sdhc card. While the desktop install iso does recognise the sdhc card, but does not support creating raid devices. Is there any way to combine the two? Or possibly create these raid devices another way with the desktop install iso? There doesn't seem to be an advanced mode for the partition manager.
Click to expand...

Yes there is although I am pretty sure it may not have even been tested with sd cards before lol. The linux software raid is very powerful. Basically install the system the normal way. Once it is up and running you are going to have to mount and partition the sd card the way that you want it. Then you will have to use mdadm to install the raid 1 filesystem onto the sd card. You will have to configure it in a failed state since you only have one disk currenly in the raid. Then format it ext3 and copy your system over to it. Then modify grub menu.lst (grub mbr will have to stay on the ssd) so that when you reboot that it will boot the system off of the sd card. They say you can't boot from sd card though? But isn't grub on the mbr on the ssd the thing that is doing the booting and then it just passes off the info on where to load the the kernel and system from? So I don't know might not work. But if it does you will be back into your system using the sd card, then you can modify mdadm to include the other drive and then it will resync with it. But that is all for raid1. You HAVE to have 2 disks for raid0 (no such thing as booting off of a failed raid 0 array :D )

So for that. You are going to have to boot off of a live cd or something and then use that to re do all your partitions if the live cd can see the sd card, ubuntu should? Then it gets tricky because you are going to have to copy all of your system data off of the ssd and onto something else, then make the raid0 file systems on the sd card and ssd (and you can't have /boot on raid0, would have to be raid 1) and then format it ext3, mount your new /dev/md0 and copy all of your data files back onto the array and reboot and pray. But actually if you are just wanting /home on raid0 you might be able to do that pretty easy even while the system is running. Just make sure that you install the system with /home already on a separate partition. Then from the running system exit out of any graphical mode and get to a terminal, like ctrl+alt+f1. Unmount /home and do the above for raid0 then mount your new array /dev/md0 onto /home.

I hope I made some sense. I am not a master myself. If you are totally lost you can try running vmware or virtualbox with 2 virtual hard drives so that you can install a guest os and create a raid set up from the beginning using graphical tools, sometimes that can help you learn. I know debian has a nice text/curses based installer and centos has a full graphical installer.

The main thing to understand with linux software raid is how everything stacks on the disk:
block device (/dev/sda) ->partiton->raid file system->virtual block device made of 2 or more raid file systems->ext3 or other linux file system

picture here: http://nst.sourceforge.net/nst/docs/user/nst_raid1.png

more info:
http://www.howtoforge.com/software-raid ... ebian-etch
 
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