RAID 5 with SSD as cache

[wayne_d]

Hi

6 x 3TB Seagate barracuda drives
1 x SSD

I have built a RAID 5 with five of the drives and keeping one as a spare.

Right after the initialization of the RAID completed my copy speed is very slow, 10 MB/s from internal drive to RAID.
I have my OS on a SSD, thinking of using a part of my SSD as cache to increase speed on the RAID.

Is it worth it, and will it affect the lifetime of my SSD drastically.

Thanks

 

[drtweak]

1) What kind of RAID card are you using?

2) Is it set for Write Back with BBU (High end RAID cards only). if there is not battery backup unit on the RAID card it is set to Write Through which has slower performance.

 

[wayne_d]

Hi,

Using motherboard ASUS H97 -plus, no RAID card.
As a decent RAID card is quite expensive, its not really an option

RAID Details:

Volatile Volume Cache Settings
Type: RAID5
Size: 11 178 GB
Write-cache buffer flushing: Enable
Cache mode: Write through

Any advice?

 

[drtweak]

Try disabling the Write-cashe buffer flushing.

You can try adding in a SSD as a cashe. Keep in mind using bigger than 2Tb drives on a RAID 5 on an onboard RAID (Which isn't a real hardware RAID) you will have slow write speeds. The more drives you have in a RAID 5 the slower it gets actually. When setting up servers for my clients we have moved away from RAID 5. We mainly stick with RAID 1 or RAID 10. RAID 10 you get best the best of both worlds and provides the max through put but you also lose half your hard drive space. You would only have 9TB and not 15TB (Preformatted that is) but you would get much faster speed out of it.

It it that or get a real RAID card. You can find them for less than a 100 bucks that can do RAID 5

 

[wayne_d]

Thanks a mill, much appreciated.

 

[AndrewBellUK]

Cache is used to increase the speed of file storing, besides it is least costly. Reduce the expenses of SSD, servers have to be used RAID with SSD, vast important files are stored in SSD frequently.