The only way to fix performance issues is finding where the bottleneck is, the first one I will look is Network, you say u are using iSCSI, are you using a iSCSI-HBA or TOE or the conversion is through software? how many hops do you have between your media server and your iSCSI device, same between client and media server, any firewall in the middle? try sending a ping with 65000 packets size between client and media and look for latecy or request timeouts.
If is doing fine, next thing will be the buffers but not necesarely the biggest buffers are the best ones, normaly are, to confirm this go to the media server bptm or bpdm and grep for delay and waited words see how many times the media server is waiting for buffers, same thing on the client side under the bpcd log, here you will see where the bottleneck is, if is on the client or media server side. Confirm the client NET_BUFFER_SZ = 262144 and must match with the media server NET_BUFFER_SZ if not change that to be the same 256KB is the biggest buffer you can configure.
Under the media server configure NUMBER_DATA_BUFFERS_DISK =128 & SIZE_DATA_BUFFERS_DISK = 262144 , because you are using iSCSI connections you can use bigger buffers, everything is still under the network.
No network issues, what about PCI slot overloaded or a bottleneck in the PCI bus, other place to look is over the I/O of the box between Swap/Virtual Memory and RAM, how is the paging doing, if you dont have enough Swap or Virtual Memory you will have a lot of paging, which can ends in performance problems.
Check for the Drive Controler Speeds and do some math
Drive Controler |
MB/Sec |
GB/Hr |
ATA-5 (ATA/ATAPI-5) |
66 |
237.6 |
Wide Ultra 2 SCSI |
80 |
288 |
iSCSI |
100 |
360 |
1Gb FC |
100 |
360 |
SATA/150 |
150 |
540 |
Ultra-3 SCSI |
160 |
576 |
2Gb FC |
200 |
720 |
SATA/300 |
300 |
1080 |
Ultra320 SCSI |
320 |
1152 |
4Gb FC |
400 |
1440 |
Network Speed |
Theoretical GB/Hr |
Typical GB/Hr |
Theoretical MB/Sec |
Typical MB/Sec |
100BaseT |
36 |
False Pict
|
12.5 |
10 |
1000BaseT |
360 |
250 |
125 |
100 |
10000BaseT |
3600 |
2500 |
1250 |
1000 |
Let us know.