All Questions
29
questions
0
votes
1
answer
403
views
How to combine an SSD with two HDDs in a RAID1-ish hybrid setup?
Coming from Linux SSD as HDD cache, I'd like to set up an SSD (or rather a partition thereon) as cache for basically a RAID1 of two HDDs. But since the data might remain cached on the SSD for while, I ...
- 388
2
votes
2
answers
511
views
Distributed SSD cache for network storage
Our small computing cluster has 3 computing nodes and 1 file server. The file server has around 70TB data to be accessed by the 3 computing nodes. All of the 3 computing nodes have 3 4TB SSDs which ...
- 21
2
votes
1
answer
4k
views
lvmcache/dm-cache writeback cache full performance
I have a SSD writeback cache in front of a HDD, set up through lvmcache (so a dm-cache). When the cache LV is not full (Data% column in lvs < 100.00%), writes go to the cache device (monitored via ...
- 23
3
votes
1
answer
991
views
Using two SSDs for Hot-Warm-Cold Caching a HDD on Linux
I currently have a debian-based Linux system that I'd like to optimize heavily. This machine has three different drives: An SLC SSD, a QLC SSD, and a 4TB HDD. I wanted to know if it was possible to ...
- 131
2
votes
0
answers
403
views
preventing big HDD's to spinup by using (small) SSD's as cache
I want to build a NAS that is as quiet, efficient and cool as possible.
In this scenario, I have the following parts:
-4 SATA connections to the motherboard.
-2 Hard drives, one is 1TB, the other is ...
- 21
1
vote
1
answer
94
views
Since VFRC feature in VMware is now end of lifed, what can I replace it with?
Now that VFRC (vflash read cache) is end of lifed in Vsphere 7, does anyone have suggestions on what I could replace it with. Looks like there is only Infinio and Virtunet in the market now, has ...
- 11
26
votes
2
answers
20k
views
Linux SSD as HDD cache
I have a Linux server system installed on an SSD and an HDD for user data. As there is space left on the SSD, I want to use it as a read cache for the HDD.
Looking at the possibilities, I found:
dm-...
- 431
3
votes
1
answer
453
views
Does issuing a sync call flush an SSD's write cache?
Suppose I create a number of directories on SSD, then issue a "sync" call.
The sync call will guarantee that any writes, even if they are stored in the write cache, will be flushed to disk by the ...
- 133
4
votes
2
answers
2k
views
DL380p G8 SSD cache
I have HP DL380p G8 with smart array P421i.
I would like to use SSD cache for my HDDs RAID 10 volume.
I got know I have to buy a SmartCache license for the array and I found some weird info about the ...
- 41
2
votes
2
answers
6k
views
PERC, Caching with SSDs
We have a few servers with PERC H710s, we're moving to SSDs and I wonder, is caching needed given that we're not using spinning disks? Our general setup is as follows
2 X 2TB SSD in RAID 1
Read ...
- 21
20
votes
4
answers
14k
views
Does a RAID controller with an NV cache improve the performance or integrity of an SSD array?
I am planning to purchase a server (Dell PowerEdge R740) with SSDs in RAID 10, and my priorities are write performance and data integrity. It will be running Linux. The SSDs have write caches with ...
- 499
5
votes
1
answer
871
views
Why is L2ARC not giving more speedup for directory traversal?
L2Arc is usually configured to cache random spinning platter reads on an SSD. I've set up this configuration in the hopes of speeding up directory traversal.
This is the setup:
# zpool list -v
NAME ...
0
votes
1
answer
2k
views
SSD cache for ISCSI block mode drives possible?
I have Debian based Openmediavault 3.0 distribution with iscsi plugin based on ietd. Among others, I use it to serve several disks as ISCSI block mode for VMWare servers. It works, however it is ...
- 1
2
votes
1
answer
2k
views
4gb cache RAID and 2gb cache RAID controllers VS SAS and SSD disks
I'm going to provision a server with 2 raid controllers, both controllers have the same specs but the cache, being one a 2GB cache and the other a 4GB cache controller, let call them respectively SC (...
- 654
0
votes
0
answers
94
views
Synology NAS X-Fer Speed Possible Issues
I recently purchased a Synology DS1815+ 8-Bay NAS for my organization and I have been running benchmarks all morning.
I purchased:
4 x 4TB 7200RPM HGST NAS (Enterprise) drives &
2 X 256GB ...
1
vote
0
answers
275
views
dmcache - is removing cache device without suspending safe?
I'm using plain dmcache for SSD cache - unmount procedure goes this way:
umount fs
suspend cache device
remove cache device
close lvm
close LUKS
shutdown
However sometimes dmsetup doesn't allow me ...
- 363
2
votes
0
answers
582
views
Poor SSD I/O performance with rTorrent and Debian
I'm using a Dell PowerEdge R210 II server with Intel Xeon E3-1230, 32GB RAM DDR3, 2 x 480 GB SSDs SATA3, 2 x 1 Gbit network connection. I'm using both network connections at the same time (802.3ad ...
- 21
5
votes
1
answer
2k
views
Adding SSD cache (PCIe) to existing Linux KVM Node with SATA disks
I currently have large KVM nodes utilizing between 8 & 16 RAID10 arrays & hardware raid. We typically provision a single large volume (VM's are backed up off site as well).
KVM VM's using LVM ...
- 51
0
votes
2
answers
578
views
How to benchmark maxCache 3.0 with SSDs? [duplicate]
We're a software development company and previously outsourced the HW side of business but now we're looking into building our own private cloud. We recently purchased a few servers, one of which is ...
-1
votes
1
answer
741
views
How to test is hardware ssd-cache work?
We have server with hardware raid controller (Adaptec ASR71605Q).
It has 10 sas HDD, 2 SSD for cache and 1gb onboard cache ram.
On server installed ESXi. On ESXi I'm start Linux, create 2Tb disk for ...
3
votes
1
answer
2k
views
flashcache with mdadm and LVM
I am having trouble setting up flashcache on a system with LVM and mdadm, I suspect I am either just missing an obvious step or getting some mapping wrong and hoped someone could point me in the right ...
- 577
25
votes
2
answers
33k
views
For L2ARC and ZIL: is it better to have one large SSD for both, or two smaller SSDs?
Main references
ZFS L2ARC (Brendan Gregg) (2008-07-22) and ZFS and the Hybrid Storage Concept (Anatol Studler's Blog) (2008-11-11) include the following diagram:
Question
Should I interpret the ...
- 635
5
votes
2
answers
2k
views
Can I use an SSD as Cache to a NAS?
There is a NAS with Raid 10 that holds resources.
At a time, around 24 machines try to access the same resource (3d rendering in a render farm).
Although the network is 1Gbps and NAS is fast, the ...
- 223
0
votes
4
answers
162
views
Does a web application which is running on SSD need in-memory caching?
My hosting provider offers me to increase my server's memory from 8gb to 24gb, at the same monthly cost of 3x 120gb SSD.
SSD choice seems more reasonable to me; but im curious if my web application ...
- 451
5
votes
2
answers
5k
views
Will adding a SSD cache device to my ZFS storage improve performance?
The server has 4GB of RAM and my zpool is made up of 15.5k SAS drives arranged like this:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1-0 ...
- 596
10
votes
2
answers
6k
views
ZFS and cache devices
I'm going to add a SSD drives to my ZFS storages as a cache. Anyone has any experience with this? What if cache device dies, will the any data be affected?
- 1,850
6
votes
2
answers
4k
views
ZFS with L2ARC (SSD) slower for random seeks than without L2ARC
I am currently testing ZFS (Opensolaris 2009.06) in an older fileserver to evaluate its use for our needs. Our current setup is as follows:
Dual core (2,4 GHz) with 4 GB RAM
3x SATA controller with ...
4
votes
5
answers
2k
views
SSDs as Linux swap for large virtual mem applications?
This question topically touched on this, but running on 64-bit Linux, I have a set of data caching JVMs as well as wanting a large web cache. Each cache today is configured to in gross fit in system ...
- 363
9
votes
5
answers
6k
views
Squid or Other HTTP Caches with SSD Cache Store?
I'm contemplating setting up a squid (or possibly varnish) cache on a system with SSD drives.
The obvious benefit is that these systems have great READ speeds and I expect my hit ratios to be fairly ...
- 5,863