5400 RPM or 7200RPM?

[WallaceTech]

This may sound like a dumb question. I usually always favour 7200RPM drives in my desktop but this was a throw back to the old IDE days. But with regards to unRaid is 7200RPM a waste or should i always stick to 7200RPM drives? Is 5400 ok becasue its SATA?

 

I can get a good price on Hitachi Deskstar H3IK30003254SE 3 TB 3.5" Internal Hard Drive - SATA - 5400 rpm

 

I am looking to host

 

MP3, AVI, MKV, Jpg and presnt and NFS share to my VMware server.

 

Thanks in advance

[siamsquare]

Yo,

 

Am also building my 1st Unraid server and have chosen a Hitachi 7K3000 3tb/7200rpm as parity disk which should increase the speed a bit.

Also I have a Samsung Spinpoint F1 HD103UJ 1TB/7200rpm as cache disk! The data drives are 5400rpm Hitachi 5K3000 2TB disks.

Just to keep powerconsumption minimal!

 

gr33tz

[WallaceTech]

Thanks for your reply.

 

What was your thinking behind the mix of 5400 and 7200?

 

Is there not a hit on performace because of the mix or am i thinking about unRaid all wrong?

[WeeboTech]

Yo,

 

Am also building my 1st Unraid server and have chosen a Hitachi 7K3000 3tb/7200rpm as parity disk which should increase the speed a bit.

Also I have a Samsung Spinpoint F1 HD103UJ 1TB/7200rpm as cache disk! The data drives are 5400rpm Hitachi 5K3000 2TB disks.

Just to keep powerconsumption minimal!

 

gr33tz

 

I like this configuration.

Fast parity drive, plus short stroking and preparation for the next version of unRAID.

Fast Cache drive. Those Samsung's can be pretty fast a reads!

[lionelhutz]

Either is fine. I have mostly WD Green drives. Those Hitachi 3T drives are great drives. I'd jump on that deal and not look back.

 

The only time a 7200rpm parity drive really helps is if you write to different data disks at the same time.

 

You are better off spending money for a single fast cache disk to increase your write speed than spending money to make every disk fast (parity and data disks) and not use a cache disk.

 

Peter

[WeeboTech]

This is highly personal to the use of the system.

 

For the average user just storing large media files, this is true.

 

If you are (or plan) running any applications such as torrenting or news downloads. Then a 7200 RPM drive on the parity and the most used data drive will provide allot more performance then realized.

 

It's stated many times that a 7200 RPM drive does little if your data drives are 5400, but if you write to more then one data drive or use a particular data drive heavily, then the 7200 RPM drive helps a bit.

 

I kept having torrent problems and delays when doing the MD5 hash sums, Plus it was bogging down writes to all the other drives.

 

Switched my torrent drive to a fast 7200 RPM drive with a 7200 RPM parity drive and all my problems went away.

 

If I could only spend money on one drive, I would spend it on a fast 3TB parity drive and short stroke it, or use unRAID 5.x. As time goes on I will probably end up buying 3TB data drives, so would I end up with a 3TB parity drive anyway.

 

If you can afford the two drives, Then go for the cache drive to get the "perceived" fast "unprotected" writes.

 

I use an Areca Arc-1200 for Parity on two RAID0 7200 1.5TB Seagate 32MB drives.

I easily get 20-30Mb/s continuous writes with Teracopy with up to a 45-50Mb/s burst on small files under 1GB.

I don't have windows 7 so I can't provide that benchmark.

 

When I move files to my XBMC with Samba, I get the same 25-30Mb/s on a single drive. So the faster parity does help.

 

Since I divide up my system to File server usage drives @ 7200RPM and Media(Movie) storage drives @5400RPM the faster parity helps.

 

It performed well enough that I moved the My Documents folder to the fileserver.

[WeeboTech]

This may sound like a dumb question. I usually always favour 7200RPM drives in my desktop but this was a throw back to the old IDE days. But with regards to unRaid is 7200RPM a waste or should i always stick to 7200RPM drives? Is 5400 ok becasue its SATA?

 

I can get a good price on Hitachi Deskstar H3IK30003254SE 3 TB 3.5" Internal Hard Drive - SATA - 5400 rpm

 

I am looking to host

 

MP3, AVI, MKV, Jpg and presnt and NFS share to my VMware server.

 

Thanks in advance

 

If it were my system, I would have a fast 7200 RPM parity drive. I would put the NFS share on a fast 7200 RPM drive.

I would put the AVI/MKV files on 5400 RPM drives.

Depending on how often I accessed the MP3/JPG files I might put them on a 7200 RPM drive or save money with a 5400 RPM Drive.

 

Where the 7200 RPM drive comes into play is in locating the files and "attributes" for the files.

 

This will be come apparent for NFS as the attributes matter plus locking needs to occur. ATIME/MTIME/CTIME needs to be updated on writes. Permissions need to be checked.

 

With the MP3/JPG files. There will be many small files on a large filesystem. When traversing the directories you will want to do this as fast as possible. When adding a new file. Reiserfs can take a while when the filesystem has allot of small files. again you will want to get through updating the filesystem tables as fast as possible.

 

Just some food for thought.

I have 20 drives, the first 5 are all 7200 RPM and contain all the data I used to keep on local systems.

 

My torrent and download drive has over 250,000 files

My picture and backup drive has over 2,700,000 files

My rsync backup has over 4,700,000 files.

My music archive has over 250,000 files.

 

The rest of my movie drives are all green 5400 RPM.

Each of these hosts between 5000 and 10,000 files.

 

The 7200 RPM drives help with the reads when I need it.

 

A cache drive will be with faster "perceived" writes.

For movie files, once the file us located the rest is all sequential reads/writes, 5400 is fine for them.

[WallaceTech]

Some great replies above guys.

 

Ok. So let assume i go for two 7200RPM drives. One for cache and one for parity.

 

If as has been said i stick movies and MP3 and NFS on a single disk......but by doing that if that disk blows up i have lost everything correct?

 

I really dont want to be in a situation where one of my drives is lost and i lose everything. I need to recover 100%

 

Craig

[WeeboTech]

If you have the NFS & MP3 disk as part of the parity protected array, then you can recover the failed disk if you replace it before another disk fails.

 

an unRAID array can handle a single disk failure.

 

Keep in mind, the cache disk is unprotected until the data is moved onto the protected array (Within 24 hours) or when you press the move button on the gui.

 

 

What do you expect to be the array's usage pattern?

 

 

[WallaceTech]

Ok,

 

So even if i stored all my MP3 for example on a single disk i could still recover it fully in the event of a problem.

 

Sorry if these are such basic questions but unRaid is very new to me. I work as Network architech and standard Raid5 i understand fully. Just trying to get my heard around this software.

[WeeboTech]

Ok,

 

So even if i stored all my MP3 for example on a single disk i could still recover it fully in the event of a problem.

 

Sorry if these are such basic questions but unRaid is very new to me. I work as Network architech and standard Raid5 i understand fully. Just trying to get my heard around this software.

 

Yes, you could recover it.

 

 

 

Think RAID4, I.E. Single Parity Disk.

Only the difference is Instead of having distributed data blocks.

The successive data blocks are on one disk.

 

http://en.wikipedia.org/wiki/Standard_RAID_levels

 

The core code is derived from the linux RAID5 code, but is modifiied to confine "successive" blocks to a single disk.

 

So in effect you have multiple filesystems that are protected by one parity.

Then an optional software later (fuse) user share that presents a bridged view of all drives so the mount looks like one large filesystem. 

 

Since all disks are XOR'ed onto a single parity disk, Only two disks need to be running for a write to occur.

If you loose a disk, Then all other disks plus parity are read to recalculate the missing block (for read, writes or rebuild).

 

For writing, the parity disk becomes a bottleneck, as simultaneous writes to disks would, in addition to the writes to their respective drives, also both need to write to the parity drive. In this way RAID 4 places a very high load on the parity drive in an array.

 

In addition, from the RAID5 area, 

 

For writes, this requires:

Read the old data block

Read the old parity block

Compare the old data block with the write request. For each bit that has flipped (changed from 0 to 1, or from 1 to 0) in the data block, flip the corresponding bit in the parity block

Write the new data block

Write the new parity block

 

So every write requires 2 reads, 2 writes.

 

Hence if you have a filesystem which is going to have a ton of small files, you want it to be a fast spinning fast access drive.

 

[WallaceTech]

Thanks mate.

 

That was the answer to my question that i was looking for. Thanks for explining it so well.

 

I so wish i had found unRaid a long time ago. Been playing with it today just on a couple of small SATA disks and i have to say i love it.

 

[opentoe]

I have 11 7200 drives and my system performs very good. I'm not a heat junkie and operate within and below specs using all default fans. In case I ever wanted to replace or use my drives for something else at least they are all 7200 performers. All have 64MB cache onboard which makes them awesome at unrarring, zipping, crunching and things like that. They also have a 5 year warranty. Who knows when a stable release of unraid will ever support 3TB. I may be "stuck" using 2TB for a while here.