VPS and raid usage

why dont web-hosting companies consider offering something like a two-tier RAID services?

maybe offer RAID-5 or faster for a small percentage of the total disk-space, and then offer RAID-1 for the rest of it?

i probably only need to get to 5% of my stuff fast, and the rest of it could be relatively slow.
 

Quags

Administrator
Staff member
I could see doing a choice of VPS on SSD drives (for speed) and the current raid-1 set up, but not a combination on the same system. On openVZ the current set up is one large partition for all accounts in that partition. Getting some data to run one one set of drives and other data on another set of drives just would add a lot of complications on top of the system. It would be easier to do on a KVM system where another drive, like sdb is added to the account where you mount it as you need. Realistically though I think the only way would be to have a choice of one or the other for the entire VPS.
 
too bad. i thought it was a good idea (as most of my ideas are).

i was thinking more like having
/slowDrive
directory off the root, and then just using symbolic links in the fast directory.

my server will probably end up with 90% archived audio/video, and speed is not an issue.
 

Quags

Administrator
Staff member
SSDs seem to be the best option for something like this. The cost for SSD is much higher than normal harddrives, so a vps offering this would offer less disk space per slice (with SSD being fast drive). Then, the slowdrive could be an NFS/samba/remote drive mount off a normal vps or our backup system (slow drive). I am considering SSD drives, for VPS, depending on demand. The disk space likely would be along the lines of 10GB per slice on a vps, down from 25GB.
 

Quags

Administrator
Staff member
Raid1 is two drives mirroring each other, so one drive can fail in this set up set up. I decided to go with raid1 / software due to its simplicity and to standardize all the servers running one raid type. Because of CPU overhead that was possible with a more complex set up running software raid I did not go with raid5 or raid10.

With hardware raid in the past, there have been many models over the years (3ware / rocketraid / adaptec etc) where each one has subtle differences for things like rebuilds The raid card adds another failure point in the system and over the years you tend to no longer have the exact replacement. There are benefits to hardware raid over software raid which of course, where hardware raid will have a speed boost depending on the model of card. In the end because linux built in raid can easily survive a motherboard replacement to a completely different motherboard model (on board hardware raid generally can not), is completely open and standardized I went with no hardware raid card and with raid1 only.
 
ok well you know FAR more about raid than i ever will (which is not saying much since i know very little).

currently at home i have a dlink dns-323 that is running raid-1. thats where my knowledge ends.

i was more thinking about the hot-swapable disk option if an interserver.net disk ever goes bad. does raid-1 offer that option?
 

Quags

Administrator
Staff member
On raid-1 if a single drive fails the server continues to run. The vps servers are hotswap still using AHCI + linux software raid, so the bad drive can be replaced and the raid rebuilt with out a reboot.
 

Quags

Administrator
Staff member
I plan on offering a separate line of SSD openvz VPS's now. There was no way to get the current VPS's to have the option for SSD on the same system. So, I expect to offer this as premium openvz vps's with pure SSD storage. It will also be Raid1 like the current set up.
 

Quags

Administrator
Staff member
The first SSD beta node is up. I expect to begin offering this as premium openvz VPS's (running on SSD systems). Besides using SSD drives (in raid1) it will also use Vswap instead of privvmpages. Additionally ploop from openvz is being considered which gives each VPS its own file system area, including journaling, to increase performance.
 

Quags

Administrator
Staff member
SSD VPS's running Vswap can be purchased through my.interserver.net now on the buy VPS page. The specs are the same as on the regular vps's for space/bandwidth and run $10 / mo per slice, instead of / 6. They are not yet purchasable from the main interserver.net/vps/ page only for currently customers currently. A general release will be available soon.
 

Quags

Administrator
Staff member
These SSD's have Wear Leveling in them that help balance out the writes to prolong the life. I've had these in service for a while, on other systems, for intensive DB applications and the intel drives are still going strong even about 2 years later. The reality is any storage media can die which is one reason we are using raid with hotswap drives. This allows the disk (ssd as well) to be replaced with out taking the entire server offline.
 
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