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Feedback on the EG Hybrid


Neil
17-08-2012, 13:35
Quote Originally Posted by Kacotet
I would like to know if it's possible to install the OS on one of the hard drives instead of the SSDs.
If you choose a Hybrid with Hardware Raid then yes it is possible to install it on to the SATA Drives since this can modified in the RAID Controller.

If it is SoftRaid then it is installed on to the SSD Drives.

Kacotet
17-08-2012, 10:50
Quote Originally Posted by Neil
Hi

Sorry what do you need confirming?
I would like to know if it's possible to install the OS on one of the hard drives instead of the SSDs.

Neil
16-08-2012, 18:54
Hi

Sorry what do you need confirming?

Kacotet
16-08-2012, 17:29
Anyone? Staff?

Kacotet
14-08-2012, 16:35
Quote Originally Posted by fozl
Not yet, we are aware that people would like to choose, and are digesting this information.

I beleive there's an issue with the way software RAID works with our manager etc, we'll figure something out.
Can someone tell me if this is still the case?

I'm looking at the EG Hybrid.

IainK
21-06-2010, 17:43
Thanks for at least getting back to people on that Fozl.

Hopefully you can get it sorted so that users will be able to choose which discs to install the OS to and save those SSDs for some high performance workloads

fozl
10-06-2010, 15:56
Quote Originally Posted by tim2718281
Any comment on this from anyone?
Not yet, we are aware that people would like to choose, and are digesting this information.

I beleive there's an issue with the way software RAID works with our manager etc, we'll figure something out.

tim2718281
10-06-2010, 15:22
Quote Originally Posted by tim2718281
It seems to me there's an underlying problem that you can't have the system boot off the rotating disks.

I wonder why not? It wouldn't have occurred to me that I'd be obliged to boot the system off the SSDs. I wouldn't necessarily want the operating system on those, so it seems odd.

I wonder if the system boot sequence could be set to SSD, rotating drive, CD, network?

Any comment on this from anyone?

tim2718281
17-03-2010, 15:34
It seems to me there's an underlying problem that you can't have the system boot off the rotating disks.

I wonder why not? It wouldn't have occurred to me that I'd be obliged to boot the system off the SSDs. I wouldn't necessarily want the operating system on those, so it seems odd.

I wonder if the system boot sequence could be set to SSD, rotating drive, CD, network?

OVHelp
17-03-2010, 15:09
Quote Originally Posted by _Lemon_
Why not? I'm pretty certain I have set up a HG Large server with debootstrap via rescue mode. What's different about these servers that prevented this?
The issue here is with installing Grub to the MBR. We are unable to install to SATA through Manager so I cannot simply boot onto that, than alter SSDs.

I just called support concerning the kvm issue - we know about it, it will be fixed soon... Been saying that for weeks.

I'm really not sure which way to turn, can't install stock Linux Distros, OVH's retarded 20GB minimum on Windows Installs and now KVM.. Incoming refund.

_Lemon_
17-03-2010, 14:58
Quote Originally Posted by OVHelp
and we are unable to use 'debootstrap' or any other custom ways to install distros through Rescue Mode.
Why not? I'm pretty certain I have set up a HG Large server with debootstrap via rescue mode. What's different about these servers that prevented this?

OVHelp
17-03-2010, 14:48
Yea, done most of all that you listed above, but keep in mind with OVH you can't (its beyond me) can't use fdisk as it wipes the drives when your doing the alignment.

Wiping SSD results in none-bootable Server obviously. Rescue mode doesn't work in this situation ethier.

Now then I thought WAIT A SECOND, I can use vkvm but HEY guess what - OVH BROKE IT...

So I'm at a loss as to what I can do to:

a) Install a STOCK Linux distro (Ubuntu Server provided by OVH doesn't install with Grub so upgrading to Lucid fails, can't install Debian 6 (Default Ext4 support) due to debootstrap now working..).

b) I know find out that bloody OVH doesn't allow a Windows 2003 OR 2008 installation to be fully Raid0, and has a MINIMUM of 20GB assigned to C: (Seriously this is getting worse and worse..)

c) Somehow to align SSDs within Linux - I'm only attempting Windows in the hope that - from what I've read atleast - Windows aligns **** properly.

Keep those suggestions coming Tim, hopefully we can both come across something that will benefit myself and others stuck in this situation.

Its an endless battle which is driving me insane...

tim2718281
17-03-2010, 14:04
Quote Originally Posted by OVHelp
Tim: The real-world application I'm seeing a terrible performance in is my SQL Database Server. The random read/write and constant sequential reads and just not surpassing what I can see from a standard SATA drive.

I will get some more statistics tomorrow during peak-hours, its not so much that the activity is causing drastic drops in speeds - its the actual performance of these drives. Apparently the alignment tweaks coupled with firmware updates are the only things left that I can try - and want to cross out but can't.

Its just disheartening that when I upgraded to the Hybrid in an attempt to stop the slow performance during peak hours, it barely matches, if not under performs my SATA drives.
I wonder if the firmware is going to make a difference to performance; Intel produced it in a hurry when it found some Windows 7 users were experiencing hardware failure when they enable Trim.

Alignment is a possibility.

For those unaware, SSDs store data in large blocks - 512K bytes for the X25M. When you write to an SSD, it has to read the block, update it, and write it back (well, that's a reasonable approximation). If the file system block bridges two SSD blocks, then writing the file system block will require updating two SSD blocks.

You should be able to control the alignment using fdisk -h and -s parameters to specify the "drive geometry" when initially partitioning the disk, picking a combination that results in a "cylinder size" that's a multiple of the SSD block size. But you might still have a problem if you're using LVMs.

I guess a similar thing applies with RAID 0; I can't see why one would configure X25M SSDs in RAID 0, but if you do, I'd think for best write performance you need to match the RAID stripes with the SSD blocks.

Actually I'd guess that's more important than alignment. Imagine writing 100K bytes with a 64K stripe size. On average, the write will start halfway through a stripe; so the first part will write to SSD A, the next 64K to SSD B, and the final part to SSD A. So the write speed could be down to 25megabytes /sec, compared with 100 megabytes/sec for a single SATA disk.

Also, I expect with SSDs it's more important to set the mount parameters in /etc/fstab to noatime,data=writeback.

And I'd guess you want to move busy sequential files (such as logs) off the SSDs.

OVHelp
17-03-2010, 13:05
Tim: The real-world application I'm seeing a terrible performance in is my SQL Database Server. The random read/write and constant sequential reads and just not surpassing what I can see from a standard SATA drive.

I will get some more statistics tomorrow during peak-hours, its not so much that the activity is causing drastic drops in speeds - its the actual performance of these drives. Apparently the alignment tweaks coupled with firmware updates are the only things left that I can try - and want to cross out but can't.

Its just disheartening that when I upgraded to the Hybrid in an attempt to stop the slow performance during peak hours, it barely matches, if not under performs my SATA drives.

tim2718281
17-03-2010, 10:32
Quote Originally Posted by Andy
Sequential = Byte after byte written to the drive sector after sector, no seeking around the drive and putting it in random places (e.g. sequential = linear).
Yes, but presumably each SSD is performing sequential reads at 250 megabytes per second. And presumably the SATA disk cannot match that speed.

So it's "sequential read/write" I'm wondering about; what does the OP mean by that, and what are the figures?

The thing is, the X25M is quite odd, in that it uses different I/O strategies depending on the pattern of access it detects. So it may be that what the OP is experiencing is actually a result of the I/O pattern combined with the SSD's attempts at optimizing perfomance.

Andy
17-03-2010, 09:57
Sequential = Byte after byte written to the drive sector after sector, no seeking around the drive and putting it in random places (e.g. sequential = linear).

tim2718281
17-03-2010, 08:34
Quote Originally Posted by OVHelp
And as previously mentioned of COURSE SSDs are going to show better READ speeds over a SATA drive, I'm talking in relation to SEQUENTIAL read/write speeds.
But what do you mean by "sequential read/write speeds"?

We know from the specs that the Intel X25M 80GB is slower at sequential writing (70 megabytes/sec) than rotating disks. So copying to SSD disks would also be slower.

But presumably you are talking about some other speed disappointment. So what are you doing, and what results are you getting?

OVHelp
17-03-2010, 04:44
hdparm, dsata, and various other benchmarks are just that. benchmarks - real-world performance is where I am disappointed.

And as previously mentioned of COURSE SSDs are going to show better READ speeds over a SATA drive, I'm talking in relation to SEQUENTIAL read/write speeds.

As such, this is where the correct aligning of drives come into play, plus firmware updates. As Linux is Open Source and constantly improving things are being discovered/created daily, as such updates are released - perfect example - TRIM wasn't supported until Kernel 2.6.33, another example Ext4 now natively supports SSDs.

The issue at hand is if I cannot actively test what is needed, it is entirely pointless OVH offering SSDs as hardware in their servers if SATA drives are performing the exact same as their 'new', 'exciting' and 'fast' SSD options.

tim2718281
17-03-2010, 04:27
Quote Originally Posted by OVHelp
The hdparm results are SSD - SATA speeds are approx 160-180mb/s - these speeds are obviously lower but the sequential Read/Write speeds are INDEF. better as explained before.
I don't understand what you're saying.

Hdparm is telling you that the SSDs are reading at over 500 million bytes per second.

What number is it the SSDs are delivering that you are unhappy about?

OVHelp
17-03-2010, 01:07
The hdparm results are SSD - SATA speeds are approx 160-180mb/s - these speeds are obviously lower but the sequential Read/Write speeds are INDEF. better as explained before.

tim2718281
17-03-2010, 00:49
Quote Originally Posted by OVHelp
the secondary SATA drives outperform the SSDs in every sequential Read/Write situation I throw at them.
What speed are you getting from an SSD?

OVHelp
17-03-2010, 00:34
As I'm sure a number of users are wondering the performance/feedback before purchasing one of these Hybrid machines I thought I would enlighten and SAVE some of you.

Over the last week and a half I have been frustratingly trying to improve the performance of SSDs within Linux - I have spent sleepless nights in astonishment as the secondary SATA drives outperform the SSDs in every sequential Read/Write situation I throw at them.

Don't get me wrong, the Random Read speeds and instant deleting (basically) is great:

/dev/md2:
Timing cached reads: 17052 MB in 2.00 seconds = 8533.87 MB/sec
Timing buffered disk reads: 1510 MB in 3.00 seconds = 502.69 MB/sec

/dev/md2:
Timing cached reads: 16706 MB in 2.00 seconds = 8360.14 MB/sec
Timing buffered disk reads: 1508 MB in 3.00 seconds = 502.50 MB/sec

/dev/md2:
Timing cached reads: 17112 MB in 2.00 seconds = 8563.66 MB/sec
Timing buffered disk reads: 1516 MB in 3.00 seconds = 504.70 MB/sec
After trying NUMEROUS Linux Distros in search of the latest and greatest (Unfortunately our FANTASTIC /sarcasm - OVH Rescue Mode doesn't allow for manually OS installation through debootstrap etc - more on this later) I ended up trailing Ubuntu Server 9.10 (also upgrade to Lucid), Debian 5 (updated to Squeeze) and BSD.

Reading numerous Forums/Articles across the internet I found numerous 'recommended' tips and tweaks which I have implemented, benchmark and tested with hardly any notice improvements. UNFORTUNATELY the last 2 and probably most major ones we cannot do with OVH - SSD Alignment and Firmware updates.

A couple articles for OVH and users to read over:

1. http://thunk.org/tytso/blog/2009/02/...se-block-size/
2. http://www.ocztechnologyforum.com/fo...-and-alignment

As you can see from the first article SSD Alignment seems EXTREMLY logical but with the way OVH has things setup there is currently no way to align the SSDs (wiping them clean in the process) and re-installing the desired OS - we are UNABLE to boot onto the SATA (so as I could work with the SSDs in live mode), and we are unable to use 'debootstrap' or any other custom ways to install distros through Rescue Mode.

Short of me having to mathematically calculate what sized partition to create so I can throw the the first SSD into alignment which is LOL

Factor in I was just quoted 60-90 pounds for someone to throw an Intel .ISO in a cd-rom drive and update the SSDs is outrageous - this should be offered, these are brand new systems and are not cheap.

I have now tried EVERYTHING under the sun:

- Disabling 'atime' and 'diratime'
- Changing of Schedulers from CFQ to Noop to Deadline
- Disabling of Swap
- Moving Logs to temp RAMDisk
- ext2, ext3, ext4, xfs and newer FS (btfs etc)
- Addition of increase 'commit' intervals, disabling of 'barrier', enabling 'data=writeback'
- Kernel update to 2.6.33 (Which supports TRIM and various fixes for SSD HDDs - supposedly)

The list is endless - I've come to the end of my tether and now speaking to my Company to assign me a Windows 2008 Server key so as I can test Winblows to see if things improve (You linux gurus out there must realise for a AVID linux user as myself over the last 10 years to consider going to Windows is quite a HUGE step..).

I ask you all to be weary, and ask OVH to look into the issue of Alignment and Firmware updates as this 'new' and 'fast' SSD equipped Hybrid range are no better then a stock SATA based setup.

- OVHelp