10.000 RPM VS 128MB Cache VS Hybrid SSD Performance

hardwarefish

Distinguished
Dec 13, 2008
39
0
18,530
We are planning to create virtualization like VPS Hosting on the server for our client in the office but the questions that been lingering around is that the harddrive and please give me some advise if possible
we are looking into 3 drives

Seagate Constellation ES.3 ST1000NM0033 1TB 7200 RPM 128MB Cache
VS
Western Digital WD VelociRaptor WD1000DHTZ 1TB 10000 RPM 64MB Cache
VS
Seagate Hybrid Drives ST1000LM014 1TB MLC/8GB 64MB Cache - HYBRID SSD

QUESTIONS IS (please answer it in order if possible, i would really appreciate it)
ASSUMING we do not use it in RAID environment just single drive

1) Which drive will perform better if we do Virtualization (which we are using KVM Virtualization on Linux server)
2) Since each drive have different role, one has higher RPM and one have higher cache and one have lower RPM (hybrid ssd but it has SSD 8GB on it) - which one will reduce I/O on the server/
3) if we used raid controller, is that right the cache on the drive itself will be disable and therefore the raid controller cache will come into the play - what i mean is, if the raid controller have 128MB cache and the bare drive have only 64MB Cache, as soon as we use raid controller that have 128MB cache, the cache for the drive will be 128MB CACHE?
4) Which drive from those 3 will be the best for read, write and reduce I/O under extreme condition


PS: I dont put SSD into the picture because of the pricing, therefore i need to know how can we create similar to SSD performance using above drives?
 

popatim

Titan
Moderator
1:All drives have known I/O and without knowing your intended I/O target all I can recommend is to get drives which exceed that.

2: Drives handle I/O, they neither create nor eliminate it. The only thing that will reduce I/O is keeping users off your server. I'm thinking we have language issue here and I'm not comprehending your intention properly.

3: If that were true then you would see enterprise raid capable drives with no cache on them, which would also make them much cheaper to make.

4: see 1: without knowing your target workload then there is no wrong or right answer.

 


If you are planning to setup a virtualization environment for a client you will need no less than 4 disks. Here's what you need:

1. A pair of redundant disks for your host partition. This is where you will install Linux and all associated host software. These can be cheap, slow, and small, but they need to be in RAID1 and nothing else. If money is not a huge constraint, get larger disks to provide some room for backing up the virtual disks.

2. A pair of redundant disks for the guest partitions. This is where you will install the guest operating systems. SSDs are best for this, but high RPM disks will do. The WD Velociraptor would be the best thing next to an SSD, but if money is tight, get a pair of 1TB 7200 RPM drives instead.